What is Omegas mark up?

It's interesting, as the 6309 isn't a movement I've serviced recently, but my recollection was that it wasn't a particularly accurate movement as movements go. I think you have to keep in mind that you will occasionally get a movement that had wild variation in positions, but for whatever reason balances out very well on your wrist. It appears accurate, but is not precise - your observed accuracy can be very deceiving.

I know you have already bough the Omega, but this bit in your first post certainly raised an eyebrow for me:

"I love divers and may go back to Seiko? Same performance and IMO, reliability for way less money. I think over the years I have been drawn into the marque snobbery trap?"

Using this example as the benchmark, one that happens to have what I would say is extraordinary accuracy for any watch, let alone a Seiko of this level, is going to set you up for disappointment no matter what brand you choose. One watch is not a statistically significant sample to judge from - just sayin'

Cheers, Al