Suggested

Total pit time loss

The quick answer to your question is yes, the pit time loss for each circuit is different.

You can easily work it out from you post race data sheet but a more accurate approximation can be obtained by running a couple of teams in a quick race / private lobby. The reason a QR is slightly more accurate is that you can manage the race to ensure neither DRS nor Boost influence the results.

I think it's unlikely that iGP will add this to the circuit details (although I agree it would be useful) because every time the devs make adjustments such as re-scaling the times change.

Anyway, to give you some idea please see here... Pit stop times