diff --git a/docs/source/usersguide/troubleshoot.rst b/docs/source/usersguide/troubleshoot.rst
index ba7e4405cc..10ac12184f 100644
--- a/docs/source/usersguide/troubleshoot.rst
+++ b/docs/source/usersguide/troubleshoot.rst
@@ -79,14 +79,6 @@ with the :envvar:`CROSS_SECTIONS` environment variable. It is recommended to add
 a line in your ``.profile`` or ``.bash_profile`` setting the
 :envvar:`CROSS_SECTIONS` environment variable.
 
-ERROR: Invalid usage of L(I) in ACE data; Consider using more recent data set.
-******************************************************************************
-
-The cross-sections requested in ``materials.xml`` do not conform to the current
-standard format.  This typically happens with fissionable nuclides in a ``.6*c``
-library as distributed with MCNP.  Please try a newer library such as any from
-the ``.7*c`` set.
-
 Geometry Debugging
 ******************
 
diff --git a/src/ace.F90 b/src/ace.F90
index e3327b2da5..d414e21f89 100644
--- a/src/ace.F90
+++ b/src/ace.F90
@@ -789,14 +789,19 @@ contains
       ! read angular distribution -- currently this does not actually parse the
       ! angular distribution tables for each incoming energy, that must be done
       ! on-the-fly
-      LC = rxn % adist % location(1)
-      XSS_index = JXS9 + abs(LC) - 1
+      XSS_index = JXS9 + LOCB + 2 * NE
       rxn % adist % data = get_real(length)
 
       ! change location pointers since they are currently relative to JXS(9)
-      LC = abs(rxn % adist % location(1))
-      rxn % adist % location = abs(rxn % adist % location) - LC
-
+      LC = LOCB + 2 * NE + 1
+      do j = 1, NE
+        ! For consistency, leave location as 0 if type is isotropic.
+        ! This is not necessary for current correctness, but can avoid
+        ! future issues
+        if (rxn % adist % location(j) /= 0) then
+          rxn % adist % location(j) = abs(rxn % adist % location(j)) - LC
+        end if
+      end do
     end do
 
   end subroutine read_angular_dist
@@ -967,24 +972,23 @@ contains
       ! Continuous tabular distribution
       NR = int(XSS(lc + 1))
       NE = int(XSS(lc + 2 + 2*NR))
-      ! Before progressing, check to see if data set uses L(I) values
-      ! in a way inconsistent with the current form of the ACE Format Guide
-      ! (MCNP5 Manual, Vol 3)
       allocate(L(NE))
       L = int(XSS(lc + 3 + 2*NR + NE: lc + 3 + 2*NR + 2*NE - 1))
-      do i = 1,NE
-        ! Now check to see if L(i) is equal to any other entries
-        ! If so, then we must exit
-        if (count(L == L(i)) > 1) then
-          message = "Invalid usage of L(I) in ACE data; &
-                    &Consider using more recent data set."
-          call fatal_error()
-        end if
-      end do
-      deallocate(L)
+
       ! Continue with finding data length
       length = length + 2 + 2*NR + 2*NE
       do i = 1,NE
+        ! Some older data sets use the same LDAT for multiple Ein tables.
+        ! If this is the case, we should skip incrementing length when it is
+        ! not needed.
+        if (i < NE) then
+          if (any(L(i) == L(i + 1: NE))) then
+            ! adjust location for this block
+            j = lc + 2 + 2*NR + NE + i
+            XSS(j) = XSS(j) - LOCC - lid
+            cycle
+          end if
+        end if
         ! determine length
         NP = int(XSS(lc + length + 2))
         length = length + 2 + 3*NP
@@ -993,6 +997,7 @@ contains
         j = lc + 2 + 2*NR + NE + i
         XSS(j) = XSS(j) - LOCC - lid
       end do
+      deallocate(L)
 
     case (5)
       ! General evaporation spectrum
@@ -1025,24 +1030,23 @@ contains
       ! Kalbach-Mann correlated scattering
       NR = int(XSS(lc + 1))
       NE = int(XSS(lc + 2 + 2*NR))
-      ! Before progressing, check to see if data set uses L(I) values
-      ! in a way inconsistent with the current form of the ACE Format Guide
-      ! (MCNP5 Manual, Vol 3)
       allocate(L(NE))
       L = int(XSS(lc + 3 + 2*NR + NE: lc + 3 + 2*NR + 2*NE - 1))
-      do i = 1,NE
-        ! Now check to see if L(i) is equal to any other entries
-        ! If so, then we must exit
-        if (count(L == L(i)) > 1) then
-          message = "Invalid usage of L(I) in ACE data; &
-                    &Consider using more recent data set."
-          call fatal_error()
-        end if
-      end do
-      deallocate(L)
+
       ! Continue with finding data length
       length = length + 2 + 2*NR + 2*NE
       do i = 1,NE
+        ! Some older data sets use the same LDAT for multiple Ein tables.
+        ! If this is the case, we should skip incrementing length when it is
+        ! not needed.
+        if (i < NE) then
+          if (any(L(i) == L(i + 1: NE))) then
+            ! adjust location for this block
+            j = lc + 2 + 2*NR + NE + i
+            XSS(j) = XSS(j) - LOCC - lid
+            cycle
+          end if
+        end if
         NP = int(XSS(lc + length + 2))
         length = length + 2 + 5*NP
 
@@ -1050,29 +1054,30 @@ contains
         j = lc + 2 + 2*NR + NE + i
         XSS(j) = XSS(j) - LOCC - lid
       end do
+      deallocate(L)
 
     case (61)
       ! Correlated energy and angle distribution
       NR = int(XSS(lc + 1))
       NE = int(XSS(lc + 2 + 2*NR))
-      ! Before progressing, check to see if data set uses L(I) values
-      ! in a way inconsistent with the current form of the ACE Format Guide
-      ! (MCNP5 Manual, Vol 3)
       allocate(L(NE))
       L = int(XSS(lc + 3 + 2*NR + NE: lc + 3 + 2*NR + 2*NE - 1))
-      do i = 1,NE
-        ! Now check to see if L(i) is equal to any other entries
-        ! If so, then we must exit
-        if (count(L == L(i)) > 1) then
-          message = "Invalid usage of L(I) in ACE data; &
-                    &Consider using more recent data set."
-          call fatal_error()
-        end if
-      end do
-      deallocate(L)
+
       ! Continue with finding data length
       length = length + 2 + 2*NR + 2*NE
       do i = 1,NE
+        ! Some older data sets use the same LDAT for multiple Ein tables.
+        ! If this is the case, we should skip incrementing length when it is
+        ! not needed.
+        if (i < NE) then
+          if (any(L(i) == L(i + 1: NE))) then
+            ! adjust locators for energy distribution
+            j = lc + 2 + 2*NR + NE + i
+            XSS(j) = XSS(j) - LOCC - lid
+            cycle
+          end if
+        end if
+
         ! outgoing energy distribution
         NP = int(XSS(lc + length + 2))
 
@@ -1094,7 +1099,7 @@ contains
         j = lc + 2 + 2*NR + NE + i
         XSS(j) = XSS(j) - LOCC - lid
       end do
-
+      deallocate(L)
     case (66)
       ! N-body phase space distribution
       length = 2
@@ -1108,15 +1113,7 @@ contains
       ! (MCNP5 Manual, Vol 3)
       allocate(L(NE))
       L = int(XSS(lc + 3 + 2*NR + NE: lc + 3 + 2*NR + 2*NE - 1))
-      do i = 1,NE
-        ! Now check to see if L(i) is equal to any other entries
-        ! If so, then we must exit
-        if (count(L == L(i)) > 1) then
-          message = "Invalid usage of L(I) in ACE data; &
-                    &Consider using more recent data set."
-          call fatal_error()
-        end if
-      end do
+      ! Don't currently do anything with L
       deallocate(L)
       ! Continue with finding data length
       NMU = int(XSS(lc + 4 + 2*NR + 2*NE))
diff --git a/src/physics.F90 b/src/physics.F90
index 5d3433f3be..3460873e55 100644
--- a/src/physics.F90
+++ b/src/physics.F90
@@ -1164,7 +1164,7 @@ contains
       ! calculate cosine
       mu0 = rxn % adist % data(lc + k)
       mu1 = rxn % adist % data(lc + k+1)
-      mu = mu0 + (32.0_8 * xi - k) * (mu1 - mu0)
+      mu = mu0 + (32.0_8 * xi - k + ONE) * (mu1 - mu0)
 
     elseif (type == ANGLE_TABULAR) then
       interp = int(rxn % adist % data(lc + 1))