What does the Calc Interval have to do with Rate and Interval Scaling?
Calc Interval is just so you can tell the CTRIO how many times you want the CTRIO to calculate the Rate or Interval scaling. In other words, if you need a more accurate measurement and are monitoring the value closely (i.e. high-speed), then calculating this value more frequently would be needed. But is would be useless to calculate it faster than the scantime of your PLC, since the PLC can only look at the value once per scan anyway. If, however, the value is not that high-speed and not needed by the process to be very accurate, then calculating this value less frequently would be better.
