Well keep in mind these times are under ideal conditions. Let's look at a real life example of how the flow can go, or not go, when servicing a particular watch...
Earlier this month I received five of the 25318000 SMP's you are getting serviced at Omega from one collector (plus some other watches), so since this is unusual to get this many at one time, I decided to try doing the services all at the same time to see if I could gain some efficiencies. The day after they came in, I disassembled the first one, put it in the cleaning machine, and while that was being cleaned I disassembled the second one, and so on until all 5 were disassembled and cleaned. I inspected the parts for all 5 and that's where things went awry right away. While I stock a lot of parts, I didn't have all the parts I needed for all 5 watches, so I had to order parts in.
Omega is pretty good with getting parts to me, so I compiled a list, placed the order on a Friday, and all the parts came in Monday....almost. Some parts are on backorder from Switzerland, and that immediately adds 2-3 weeks. So I have 4 of the watches serviced and in final testing, but one is still in it's fully disassembled state as it was the day after I received it, and it's been that way for 2 weeks now. So if these were all from different people and yours was that last one, then you can see that getting this done in a week is not going to happen. And I pull parts from the same stock that the service center uses, so if they are out of the parts, it's not just my job waiting, it will be all the watches of this type that the service center is servicing at the time. People here have stated that when they track the status of their repair at an Omega service center, that sometimes "waiting for parts" comes up, and that's when the parts are coming from Switzerland to wherever the local service center is, so it does happen.
The time required also depends a lot on how the testing is done after service. There are certainly watchmakers out there who adjust the rate to one position, case it up, and call the watch done. For me (and for Omega) that's not a proper testing regime. My post service testing lasts 10 days in itself, and that is at a minimum. I test the watch for 24 hours in each of the 6 positions, plus 24 hours on the final test winder to give me an idea of how it will wear on the wrist, and then test the run time buy letting it run down until it stops. If at the end of the test I find the average rate is fast or slow, I adjust the rate and run the test again.
So for me personally, there's no way I will finish a mechanical watch service and have it back in a week...but people want different things from their watchmakers clearly. I'm sure the wait is annoying to some, but doing the job right takes time.
I think using the best case scenario and saying "it should take a week tops" is probably pushing things more than a little.
Cheers, Al