How do you ask your tech what settings they are using on you without coming off like you’re doubting their knowledge/skills? I always feel uncomfortable asking because a. they have the job for a reason, because they’re supposed to know what they’re doing and b. I don’t want to come off as someone that thinks they know just because they have access to the internet. I feel rude for asking. But at the same time I want to know that I’m getting my money’s worth. Helppp?
Good Q as I often struggle not to come off like a jerk… Or freak 
More seriously, I would say asking their opinion/advice first and for them to clarify is perfectly reasonable. Then saying I’ve heard/read that is too low for perm results or discussing until you reach a level that both are you are comfortable is appropriate. Sometimes this is easier than others and esp when based on exp ie some more junior will follow a chart/guideline and not want to risk burning/hurting you. This isnt a bad thing by any means 
But if they refuse point blank, then discuss doing spot tests in advance of a treatment to test your skins reaction and to adjust your treatments accordingly. At end of day, you are a paying client and they are just trying to take good care of you. I do think there are economic drivers given to maximize treatments by some ie if you do treatments every 6 weeks rather than say 8-10, then you’ll end up spending more overall. That said, arm yourself with knowledge from here instead of blind acceptance and you can make that call. when i speak to anyone with more specialized skills than myself, I always ask a few questions to ensure it meets my expectations. Exactly the same applies But then again, I’m a freak