The accuracy difference was squirrel-eye accuracy at 50 yards, compared to barely staying on a squirrel's head. To me, that's significant.
If I was going squirrel hunting with my .32 & knew no ranges would be over 25 yards, I could get away with 20gr. of 3F. If shots could be presented at 50 yards, I'd have to use 35gr. 2F. At 25 yards, 20gr. will make a hole for 5 shots the size of a dime, but at 50 yards, you couldn't stay on a squirrel's body - not even a fox squirrel.
If shooting at 25 yards in a contest, then, of course, you could get just about as good accuracy with less powder in the .40 as well - but not at 50 yards or farther - not with a very slippery lube, that is, in my .40. The more slippery the lube, the more powder it usually takes to get the best accuracy in any barrel.
Too - the slicker the barrel, the more powder it takes.
In my .40 water based lubes like WWWFluid with a few ounces of Neetsfoot oil added allows charges as low as 50gr. 3F to shoot decently out to 50yards, 65gr. 3f in the .45 - the Lehigh Valley Lube didn't allow such light charges in either rifle. It took powder to make them shoot, but man, did they ever shoot well - cleanly too, and loading was a snap, even with 75gr. 2F in the .40 and 85gr.2F in the .45 - never a difficult loading, nor any buildup of fouling shot to shot. The greased patch load in the .45 is 75gr. 3F. I know several guys who shoot only that much 2f in a .50 and one guy 65gr. 2f in his .62. They all suffer from trajectory and/or accuracy problems at the longer ranges. I'd rather not.