Seikos can be prone to problems with the hairspring becoming snagged if the watch gets a knock. If the watch is fairly new it shouldn’t need a service, I’ve fixed this fault by carefully removing and refitting the balance, I prefer this rather than trying to free the spring using the fine tweezers. Removing the balance allows the spring to be inspected, if it looks OK no correction or truing up is needed and the watch should run OK. This can be confirmed on the timegrapher, if amplitude and positional agreement are OK minor regulation may be needed but that’s all, in most cases the snagging of the spring doesn’t result in any changes in how the watch runs.
The watch may need a service if its a few years old and it may need the beat error correcting, Seikos are notorious for being slightly out of beat, but that’s an east adjustment tgat can be made when regulating the watch.