1) Please see my earlier reply on how to identify same transponder numbers. Moreover, while recording is going on, if we press the OK button in the remote control, it displays channel numbers that we could switch to in white. Other channel numbers are greyed out. That is one way to safely switch to another channel without the worry of the recording getting stopped.
2) However, Tata Sky and Airtel cost us money even for allowing us to record anything, don't they? I guess we might want to take the good with this obvious disadvantage.