To fill in some other background, Rebounding is a stat that is lagging in both the PFs (both inept, lower than almost all other stats). Only the C, Cassia, has decent rebounding already (respectable).
If I understand what you’re saying, then, is that training levels are rounded. So what probably happened is that that the one player that popped probably had a Rebounding level of, say, 6.4, and his 9 minutes of playing time got him to 6.5, so he popped to respectable. And similarly, Gaffney probably had a Rebounding level of, say, 3.5, and after 91 minutes, he’s now somewhere about, say, 4.4 in Rebounding.
Am I starting to get it?
Don't ask what sort of Chunks they are, you probably don't want to know. Blowing Chunks since Season 4!