ERS,
The only thing I can say is that it *should* not decrease QoS, except the TCH traffic and SDCCH traffic.
Of course, there are always small chances that something unpredictable happens. But in your case, I can’t think of anything. So it is a pretty safe trick, as long as you don’t care about traffic.
(sorry to emphasize so much on traffic…)
Cheers,
pix