Unless I've forgotten, I think the conclusion was that precision attack was equivalent to adding that 3-4 DPR per attack when using sharpshooter against a 20 AC opponent. This didn't account for what if any effect sharpshooter was adding without precision attack. It also didn't account for the effect of crossbow expertise's bonus action attack.
Also, I'm curious how much DPR you think is typical?
A level 10 Battlemaster longbow archer will do about 15 DPR against a 20 AC target using the 1d8 damage dice maneuvers with 24 combat rounds in the day. (Action surge not included)
A level 10 Battlemaster CE SS archer will do 27.75 DPR against a 20 AC target using precision attack. (Action surge not included).
The DPR difference in the builds is 27.75 - 15 = 12.75 which comes out to the CE SS doing 85% more damage than the fighter that takes neither feat.
Just for fun, the best case DPR against that 20 AC enemy that you can hope to achieve if you leave out just one of the feats is 19.5 by leaving out crossbow expertise. (It would be 19.125 if you left out sharpshooter and took crossbow expertise). That's only maybe +4.5 DPR compared to the guy that didn't take the feat. Speaking of +4.5 DPR is still about a 30% DPR increase.
I'll be honest. I really shouldn't have to explain these basic things again and again. Ya'll really should try to think before you open your mouth and post a quick and hasty reply that just shows ignorance.