I would need more sound demos to be sure what it‘s about. In the example Fran posted we have two arrangers released about 6 years apart, which is not a long time. As Roland Europe squeezed about 2,000 sounds into the BK-9 and the company was already on its last legs, I‘m not completely sure they didn‘t play tricks with compression here, but the Tyros 4 vs. 5 case is a totally different one again.