diff --git a/src/davidson/davidson_parallel.irp.f b/src/davidson/davidson_parallel.irp.f
index 32f89979..10b41f4c 100644
--- a/src/davidson/davidson_parallel.irp.f
+++ b/src/davidson/davidson_parallel.irp.f
@@ -438,7 +438,7 @@ subroutine H_S2_u_0_nstates_zmq(v_0,s_0,u_0,N_st,sze)
   ipos=1
   do imin=1,N_det,tasksize
     imax = min(N_det,imin-1+tasksize)
-    if (imin==1) then
+    if (imin<=N_det/2) then
       istep = 2
     else
       istep = 1
@@ -505,7 +505,9 @@ subroutine H_S2_u_0_nstates_zmq(v_0,s_0,u_0,N_st,sze)
     print *,  irp_here, ': Failed in zmq_set_running'
   endif
 
-  call omp_set_max_active_levels(4)
+
+  call omp_set_max_active_levels(5)
+
   !$OMP PARALLEL DEFAULT(shared) NUM_THREADS(2) PRIVATE(ithread)
   ithread = omp_get_thread_num()
   if (ithread == 0 ) then
diff --git a/src/determinants/spindeterminants.irp.f b/src/determinants/spindeterminants.irp.f
index 765ee394..dea4a566 100644
--- a/src/determinants/spindeterminants.irp.f
+++ b/src/determinants/spindeterminants.irp.f
@@ -1075,19 +1075,17 @@ subroutine get_all_spin_singles_and_doubles_1(buffer, idx, spindet, size_buffer,
   integer                        :: i
   include 'utils/constants.include.F'
   integer                        :: degree
-
+  integer                        :: add_double(0:64) = (/ 0, 0, 0, 0, 1, (0, i=1,60) /)
+  integer                        :: add_single(0:64) = (/ 0, 0, 1, 0, 0, (0, i=1,60) /)
 
   n_singles = 1
   n_doubles = 1
   do i=1,size_buffer
     degree =  popcnt(  xor( spindet, buffer(i) ) )
-    if ( degree == 4 ) then
-      doubles(n_doubles) = idx(i)
-      n_doubles = n_doubles+1
-    else if ( degree == 2 ) then
-      singles(n_singles) = idx(i)
-      n_singles = n_singles+1
-    endif
+    doubles(n_doubles) = idx(i)
+    singles(n_singles) = idx(i)
+    n_doubles = n_doubles+add_double(degree)
+    n_singles = n_singles+add_single(degree)
   enddo
   n_singles = n_singles-1
   n_doubles = n_doubles-1
@@ -1113,15 +1111,14 @@ subroutine get_all_spin_singles_1(buffer, idx, spindet, size_buffer, singles, n_
   integer                        :: i
   integer(bit_kind)              :: v
   integer                        :: degree
+  integer                        :: add_single(0:64) = (/ 0, 0, 1, 0, 0, (0, i=1,60) /)
   include 'utils/constants.include.F'
 
   n_singles = 1
   do i=1,size_buffer
     degree = popcnt(xor( spindet, buffer(i) ))
-    if (degree == 2) then
-      singles(n_singles) = idx(i)
-      n_singles = n_singles+1
-    endif
+    singles(n_singles) = idx(i)
+    n_singles = n_singles+add_single(degree)
   enddo
   n_singles = n_singles-1
 
@@ -1145,14 +1142,13 @@ subroutine get_all_spin_doubles_1(buffer, idx, spindet, size_buffer, doubles, n_
   integer                        :: i
   include 'utils/constants.include.F'
   integer                        :: degree
+  integer                        :: add_double(0:64) = (/ 0, 0, 0, 0, 1, (0, i=1,60) /)
 
   n_doubles = 1
   do i=1,size_buffer
     degree = popcnt(xor( spindet, buffer(i) ))
-    if ( degree == 4 ) then
-      doubles(n_doubles) = idx(i)
-      n_doubles = n_doubles+1
-    endif
+    doubles(n_doubles) = idx(i)
+    n_doubles = n_doubles+add_double(degree)
   enddo
   n_doubles = n_doubles-1