I suggest you ask for a second opinion from another company. If you're around Reston, you can check this HVAC company that we always contact: https://cloverco.com/service-area/reston/hvac/. They are reliable, and their service costs seem to be reasonable.
Sounds cheap to me. No company is going to stay in business charging for a lowball price on refrigerant. That $85 probably doesn't even cover the overhead of a trained tech in a stocked van at a call
Getting a second opinion from a reliable company is your best option. These professionals will give you honest advice and quotations. Also, you can ask them to explain to you the breakdown of the cost so you'll have a better understanding. You can check this article by Hurliman Heating if you want to see what a reliable company looks like.
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