Jim and Mike have emphasized an important point. I used to think the same thing: how can a grain or two difference in powder make much difference in recoil, assuming velocity and payload are constant? It's because the powder carries more "weight" in the formula.

The felt recoil thing is tricky, to say the least. The late Bob Brister--another guy I think most of us would say was more than just a "gun writer" too--believed that backboring and lengthening forcing cones reduced recoil. He also refers to ear protection as being one of the most effective ways to reduce felt recoil--or, perhaps in this case, we ought to call it "perceived recoil". The louder it sounds, the harder you expect it to kick. We probably don't want to sidetrack into a discussion of those points, but they--and a number of other factors, like gun fit--impact "perceived recoil".