Precision is a statistical term that can be quantified, either absolutely from data, or relatively as in “this method was more precise than that method”.
When you have a force of 500 bombers, precision is difficult to achieve for many reasons: variation in the skill set of individual crews and/or leaders, target obscured by smoke as the raid progresses, etc.
I am aware of only one heavy bomber unit that was actually achieved both accuracy and precision and that was 617 Squadron. It was a specialist unit, specifically trained in precision bombing and it achieved success repeatedly over its 2 year existence. It was remarkable, really of what it achieved With dumb, unguided ordnance. Perhaps there was a similar unit with the USAAF, but I am ignorant of the existence of such units.
And No. IX Squadron, every bit as good, some would say better, than 617 at that precision coming lark.
USAAF didn't have an equivalent unit, but they were going to stand up specialist B-29 units for the invasion of Japan carrying either one Grand Slam or two Tallboy bombs.