CP Formula Question on Abras

Okay I have 2 Abra Hatches

645 CP Top Rating Defense Top Rating
635 CP Top Rating Attack Defense Top Rating

Put them in calculator, expecting at least a 2 point IV difference between them.

645: 20 14 13 15 42/45 (93.3%)

635: 20 11 15 15 41/45 (91.1%)

Generally because the Attack Value matters more in the formula, I'd have expected 2 points of attack to be really close, and even higher than 3 stamina.

What am I missing in logic