1/ the detection of radio call drop is altered, you might notice a decrease of radio call drop. But it’s just because subscribers are hanging up rather than waiting for the call to drop. (this is especially true in “downlink-limited” cells). Your CDR is artificially decreased. Therefore you should change your KPI threshold in order to take this into account (instead of threshold = 1.2%, you use 1.0% for example)
2/ the BSS keeps the TCH timeslot reserved for a call as long as the radio link timeout is not expired. So your radio resources are wasted.