[Rafal Lukawiecki]

interesting stuff.
I'm also a complete beginner with tray development of sheet film, developing them singly and - knowing no better - using only rocking for agitation.
I've done about a dozen or so now and they are all quite adequately dense.

(Not trying to deny what you're saying Rafal, just offering a different experience)

Pdeeh, if it works, it works, stick with what you are doing. In my original post, I was specifically contrasting a "gentle rocking" of a tray to fairly vigorous tank inversions, which would be a cause for a difference in densities, between two methods, all else same. However, as Doremus, and Ian helpfully explained, there are many ways to get the tray agitation right, which I believe must also be your experience. If ain't broken...