diff --git a/code/code_gen/post.py b/code/code_gen/post.py
index a6125dc..6d38021 100644
--- a/code/code_gen/post.py
+++ b/code/code_gen/post.py
@@ -966,9 +966,9 @@ close (200)
 
         declarr, allocarr, freearr = self.work_array_codes()
 
-        declavg  = "\n".join(v.code_decl() for v in self.averaged.itervalues())
-        allocavg = "\n".join(v.code_alloc() for v in self.averaged.itervalues())
-        freeavg  = "\n".join(v.code_free() for v in  self.averaged.itervalues())
+        declavg  = "\n".join(self.averaged[v].code_decl() for v in sorted(self.averaged))
+        allocavg = "\n".join(self.averaged[v].code_alloc() for v in sorted(self.averaged))
+        freeavg  = "\n".join(self.averaged[v].code_free() for v in sorted(self.averaged))
 
         decl_export  = "\n".join(v.exporter.code_decl()  for v in set_export_on)
         alloc_export = "\n".join(v.exporter.code_alloc() for v in set_export_on)
diff --git a/code/termspecs/termspec.fsd-pos-neg b/code/termspecs/termspec.fsd-pos-neg
index c0be898..a7c945a 100644
--- a/code/termspecs/termspec.fsd-pos-neg
+++ b/code/termspecs/termspec.fsd-pos-neg
@@ -12,9 +12,17 @@ nz(latex="n_z") = - ddz(c) / fsd
 
 divn(latex="\nabla \cdot \vec{n}") = ddx(nx) + ddy(ny) + ddz(nz)
 
-divn_plus = $positive(divn)
-divn_minus = $negative(divn)
+divn_sign = $dsign(1, divn)
+pdivn_mask =   $positive(divn_sign)
+ndivn_mask = - $negative(divn_sign)
 
-avg { c, u, v, w, fsd, ddx_c, ddy_c, ddz_c }
+fplus (latex="\Sigma_f^+'") = pdivn_mask * fsd
+fminus(latex="\Sigma_f^-'") = ndivn_mask * fsd
 
-avg fsd { u, v, w, nx, ny, nz, divn, divn_plus, divn_minus }
+avg { c, u, v, w, fsd, fplus, fminus, ddx_c, ddy_c, ddz_c }
+
+avg fsd { u, v, w, nx, ny, nz, divn }
+
+avg fplus { divn }
+
+avg fminus { divn }