If it's just an upgrade of IPO (500v2) and VMpro, without having to switch vm servers, then I usually budget 2 hours for a simple backup and upgrade and get it done in less. (Of course this depends on what release to what release I'm upgrading to and if there are any extra steps to make it jump through, going from 5.0 to 9.1? I will budget more time to make sure all is in place correctly, and move through the required multiple steps. 9.0 to 9.1 should take around 2 hours max, 3 if you got slow connections/PC and working remotely.)
If I can be onsite then the SD card way works the fastest as others have mentioned. If I'm remote, I don't sit there and stare at Manager uploading files to the SD card, and will come back to it after an hour and see if it completed fine. I do document the number of registered phones and watch them upgrade and make sure they were all successful and re-registered. (Either digital or IP)
I have never billed a customer 7.5 hours labor for an upgrade. That would be a different scenario (large SE customer with many extra's, large SCN, or if hardware failed during the upgrade process.)
'avaya platinum partner' doesn't mean they work faster or "know" more, it means they have more people with the required accreditations and probably work slower with more hoops of paperwork to jump through within their business model. More hands touching the same project and all want to get paid on it.