diff --git a/cscripts/csspec.py b/cscripts/csspec.py
index 3a9bc48..801704b 100755
--- a/cscripts/csspec.py
+++ b/cscripts/csspec.py
@@ -1024,14 +1024,16 @@ class csspec(ctools.csobservation):
         # Compute the flux values to evaluate loglike at
         log_norm = math.log10(norm)
         if (norm_err > 0.0) and (norm > norm_err):
-            log_step = log_norm - math.log10(norm-norm_err)
+            log_step  = log_norm - math.log10(norm-norm_err)
             log_start = log_norm - (sigsteps/2) * log_step
         else:
             # For an upper limit bin use a broad range of steps in flux
             # from [10^-24, 10^-14] or [norm, 10^-14] whichever is broader
-            log_start = -24 if (log_norm > -24) else log_norm
-            log_step = (-14 - log_start) / (sigsteps-1)
-        norm_vals = [10 ** (log_start + i*log_step) for i in range(sigsteps)]
+            log_start = log_norm
+            if log_start > -24.0:
+                log_start = -24.0
+            log_step = (-14.0 - log_start) / (sigsteps-1)
+        norm_vals = [10.0 ** (log_start + i*log_step) for i in range(sigsteps)]
 
         # Loop through normalizations
         flux_par.factor_min(0.0)