Hi Suresh,
Unless these parameters are extremely low, they will not have that much impact on your TBF drop rate. In fact, I think sometimes it’s better to drop the TBF and re-establish it, rather than wait for a long time for a response from the MS or BTS (which is what these parameters essentially do).
I think you should focus more on main causes of TBF drop, such as poor radio conditions, initial coding scheme, hardware faults, capacity, pre-emption, etc.
Regards,
SHELDON