i will normally swiss brand charging generally 10% of its watch value for servicing with a reason!
they use full proper machine and tool, use only original new parts, use correct oil and gasket, proper trained technician, give new warranty, testing going through QC spec, etc
watch its recommended for servicing every 5-6 yrs except some with new tech.
plenty of trained technician doing side jobs
its common since their day job pay is not high
anyway, generally i would not recommend to send your watch to those who charge super low.
bcoz,
1. the original parts is not cheap
2. swiss made tools and good machine cost you alot
3. proper training also cost you a bomb
unless you know who is the guy taking your watch away for weeks.