Sometimes it feels like you do almost just as much work overlaying when someone needs heavy prep and such, but since you don’t do any extending of the nail you use less products so in theory you should charge a little less. But it’s not only product cost to consider, it’s also your time costs. So if you feel you can’t get the time down on doing overlays compared to extensions than you should consider matching prices to your time spent, not consider what you’ve done to the nail. Hope this helps, Ive been there and still are sometimes so it’s confusing, but you have to figure out what works for you so you can make money and have happy clients. Don’t worry about their wallet, just the quality of your work.