Is the bow currently shooting well and fit you good?
You have a couple options depending on the shop. If your setup is shooting good, and your concerned about the strings "changing" every thing, then ask the shop to reset everything to current measurements. This is not so hard to do, but requires a bit more time. The tech should pull your current DW, exact DL using measuring arrow, ATA, BH, distance from nock point to peep, and timing. With those measurements the bow will come back to you Ready to go.
The problem. Most of the time strings and cables jobs go hand in hand with the bow having lost poundage, draw length stretched a bit, or timing being off. Generally the customer wants it returned to factory specs and tuned. Peep measurements are easy to pull and will put the peep back in your eye, but depending on your shooting form it may or may not need tweaked to you. This is very difficult to do without the shooter and in person tuning would be preferred if possible.
I typically do all my own work but there was a shop opening near me and I decided to give them a try, and save me the job installing my strings. They asked if i wanted it tuned and I had them do it. My peep came out in the right spot but was not what i consider fully tied in. Included was a cut out of a bullet hole when asked if i needed to shoot it, they replied "the tech had tuned it well, and spent some time". To be fair it was very close. A small rip low and right for me, but I could clean it up without moving my rest out of center shot,, or moving the string. The bow was shooting well with just some sight adjustments prior to making tuning adjustments, so I probably would have never noticed if not being nitpicky. But IMO the shop should take the time to make those tuning adjustments for you and hopefully save you some headache with further tuning or BH as well as a solid tie in job. Perhaps I caught them on a bad day or the guys behind the counter weren't experienced. Overall I felt a bit overcharged for the work since I also waited a week and brought them strings, but it certainly shot well enough and nothing was way out of whack so I was satisfied.