From my understanding, that's exactly what's happening. BB v0.4 has it set so there is always 50MB of free memory.
Yes but I'm not familar with exactly
how it's keeping that memory free, Autokiller (or MinfreeManager is another app) manages the many different thresholds at which Android kills programs and what type of programs it kills. So you can keep memory free two different ways. First by say keeping "empty" apps out of ram, which are apps you aren't using but may use, they don't use battery or cpu cycles they just sit in RAM. Or you can free memory by killing content providers (like sync), background apps, and even the foreground app.
by say ensureing that empty apps get "killed" quickly say at 70 mb free, you are less likely to hit the much lower (like 30mb) threshold for background apps.
BUT!!! after some more research (via launcher pro forum and various dev IRC channels) I think the real problem is that Android doesn't handle multiple HOME apps very well, and handles proxy home apps (like quickdesk) even less.
Try this. Uninstall all home apps but LauncherPro, even the stock Launcher2, or at the very least remove all shortcuts and widgets from the other home apps, and see if that helps.
I removed ADW and Launcher2 and I
haven't had a single redraw since then I installed quickdesk to test, and they began right up again, same with ADW.