have you tried turning it back on ? the same thing happened to me, ul estab = terrible for many cells. It started this way :
I enabled the PC UL GPRS. Everything worked fine for a while. Then suddenly the UL estab decreased terribly. As a troubleshooting procedure, UL PC was deactivated, and that solved the problem !
I think i re-enabled it for test trial, and it worked fine also… very weird. It might be due to some MS not supporting UL GPRS PC (??).