Is $1,600 to repair a blister/wrinkle on a flat roof a fair price?

I recently moved into my townhouse unit in Toronto, which has a flat roof. I noticed some long blister/wrinkle lines on the surface that haven’t broken open yet but are quite visible. I'm wondering how serious this type of blister/wrinkle is if it hasn’t split yet, and if I should fix it right away or monitor it. I'm also unsure if a simple cut/dry/patch with roofing cement and new membrane patch is sufficient, or if a roofer would recommend a bigger section replacement. I've reached out to a few roofers and received this quote. I believe I should address this issue as soon as possible to prevent further problems.