At one point in the middle of the Pega use case development effort, my team and I were given one day to produce an estimate of the number of hours remaining in the use case development effort. The below is the result of that quick turnaround. In general, the estimates were a bit on the low side but reasonably accurate (within twenty percent).
Pega BA Use Case Estimates page 1
Pega BA Use Case Estimates, page 2