When I got into shooting muzzleloaders (early 1970s) I often attended a local monthly shoot. At those matches it was home cast round ball loads, and almost everyone used a "spit patch" of pillow ticking. I've seen many amazing groups at up to 100 yards, and shot a few myself.
The bouncing the ramrod was not used often, but it would confirm the load was seated if the shooter was in doubt. The spit patch kept fouling down, but occasionally a load just didn't feel like it was seated right, and the bouncing the ramrod would remove (or confirm) doubt.
I never saw much effect on accuracy from just bouncing of the rod on the ball. The ramrod would be lifted up about half the barrel length and allowed to fall using gravity and it's own weight. If it made a dull thud and didn't bounce the load wasn't tight against the powder, if it "rang" and bounced everything was fine.
In those matches a complete miss wasn't counted, so if the ball had to be hammered down on the powder you could just miss paper & shoot again.