No real reason to question what numbers you have come up with
... they are what they are !
* But you can double check them by using your degree wheel a bit differently. Rather than the "ZERO" being TDC and working your port duration numbers from that, Do this:
* On the port your working with, At opening point, make that your "Zero", as port closes the degrees of duration will be an exact number.
Repeat on EACH port for a much more precise measurement.
Scott