Testing a jazz style, I do hear fills for each part marker, including several in a row. I can turn off the fills before a part marker, and I can also force a fill where there is no part marker.

I think the subtlety in what you may be hearing is caused by where in the phrase you put the fill, or don't put the fill. I think, with no evidence other than my ears, that the drummer who recorded the RealDrum part just naturally is more likely to put some fill-like pattern every fourth bar, for example. You can ask for a fill in the first measure of a phrase leading to measure two, but it's not as musical and the drummer won't emphasize it.

It is worth more testing.

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