hi S,
Recall I said in a counter it is usual to Reset/Clear all the Bistables in order the counter starts from '0000'.
This is because at Power On the individual Bistables can be Set or Clear, so when counting starts it may not be '0000'.
Consider that you wanted the counter to start at '1100' , what if you could Set 'A' and 'B' to'1' state, how would you achieve that.??