Performed ac maintenance, replaced the upstairs filter for homeowner. They will have high merv rated filters at the next visit. Usually she uses merv 12-14 filters due to allergies. They mentioned that the downstairs seems to have difficulty cooling, checked system and found that the high stage cooling wire had slipped off of the the furnace terminal strip so system was only running in low stage for downstairs. After that minor repair the system kicked into high stage. Upstairs and downstairs are cooling great. The only recommendation that I have is to to install the two start assist kits for 10 year old compressors to extend their life.