I think leverage is overrated to some extent. Adding 10 lbs of fat ain't gonna boost anyone's bench by 30 lbs. Yes, there is a benefit, but it's subtle.
When I diet, the first lift to go down is my bench, in all variations. Immediately following is military and other shoulder pressing - so all pressing exercises decline first. In fact, I will experience strength declines in these lifts well before I decline in squats/deads/rows etc, when one would think it would be the opposite. This is all before large amounts of fat have been lost, mind you.
Likewise, when I resume maintenance or above maintenance kcals, I will notcie almost immediate improvements pressing. Again, this is before I've really gained back any weight, other than a few lbs of water weight. T
his is all anecdoatl, of course, but in my experience, there seems to be some correlation between caloric intake and pressing performance, independent of fat gain or loss.