"I'm curious about these two:-
(Q1) 4...cheapo China movement or quality swiss etc movement
(Q2) 5...genuine watch or replica
(Q3) If it's purely a service, no parts needed, and assuming any rep movements are built to a reasonable standard so they're as easy to reassemble as a gen, why would the time to do the service vary?
(Q4) Or are you varying the charge for the same amount of work to match expectations of gen and rep owners?"
My posts are still coming up under the wrong name but I am still 'automatico'...far as I know.
Addressing Q1 & Q3...It takes longer to service 'China junk' than swiss Eta etc. Why? Because much the CJ is basically hard to work on. Date works on Miyota clones (NN, DG etc) are a pain for instance and the 3/4 plate construction is a real hassle. They are made to sell, not to work on. I have had so many apart that I am pretty fast on them but still do not like to work on them at all. Imho the Seagull ST16 'magic lever' Miyota clone is the best of the bunch and the tried and true Seagull ST6/ST6Date is also OK but the date works are somewhat fragile. The ST6 is made in the traditional manner with the autowind assembly screwed to a basic hand wind movement. The Miyota clones and ST16 are 'integrated construction' with the autowind parts under the same plate that covers the train wheels. The ST16 uses the Seiko type 'magic lever' type autowind device where the NN, DG etc use a reverser. The Asian etaclones (2824/36) are better but need c/o more often than not when new because of poor QC and storage/assembly conditions, most parts are relatively hard to get. Swiss Eta 2824\36 are relatively easy to work on and parts are easy to get.
Addressing Q2 & Q4...Many repair guys charge more for higher grade movements depending on price and availability of movement parts. Flip a DG pallet fork into oblivion and you are out $1 or maybe nothing for a replacement...flip a rolex 1570 pallet fork and you are out $100. Kill a DG hairspring and you are out $5 for a 'balance complete' from another member...kill a rolex 1570 hairspring and you are out $350 to $500 for a 'balance complete' from a seller who has you by the short hairs. You are taking much more of a risk when working on expensive watches/movements. It is easier to satisfy someone with a NN/DG/Seagull movement than a swiss Eta, omega, rolex etc...at least it should be in the real world if the NN/DG/Seagull owner understands what they have.