Lots of talk about a string loop on another thread. I have a question.....

I know VERY LITTLE about bow set-ups.....but I KNOW "I" like a very small string loop (just big enough for my nock to fit in and get my release on).

Why would my bow shop be somewhat reluctant (it seems) to make my string loop the size I want it????? They always make it bigger (though not as big as many I see) than I want it.

just rying to learn......