Wierd memory loss

Hello folks
Something strange has happened lately and I need your opinions

I have a BB bold 9000 that was on OS .411 and free app memory was around 42 millions after rebooting

Last week I installed the latest beta OS but was not happy with it so I went back to .411

I am on the fourth day on .411 now with the exact same applications but memory is down to 32 millions after rebooting ?!?!?

Isn't that wierd ??

In both cases I used BBSAK to wipe my device and remove the same unwanted codes and languages

Opinions? I am going crazy