In my case, I don't think they reviewed my file until my LOR was in (tho mine was a committee letter so it might be different with 2 out of 3). My app was received by them mid-August, however my health advisory board was really behind in writing committee letters and mine was not received by UoP until the beginning of October. 😡 To date, UoP is one of the few schools I have not heard from and, at this point, probably will not hear from.
i called to make sure because i had the same issue. the lady at the admisisons office told me that they will put your file on hold until you have all the requirement.
but then again, looks like some people here got interviews with incomplete files, go figure!