Just now used Best in Bags for my paladin. For prot spec, it suggested the 320 Spearfisher’s Band over the 325 Spearfisher’s band. Clicking in for the details shows it somehow computes the 325 as -0.15% worse.
Your gem and enchant preferences isn’t the same as spec priority. My guess is the same as Cluey, you have prot spec as a lower priority. So the 325 is taken by another spec with one enchant, and your prot get the other ring with a different enchant since it isn’t allowed to change the enchant for the higher priority spec.
There are no enchants and no gems on any of my gear, and my preferences say not to put any on them. This preference is honored in the best in bag output which specifies “No Ench” in the enchantment slot. Since there is no enchantment, there is no reason the better ring could not be allocated to each spec. Or am I missing something?