Automatic/Zone Damper Question

I have a Goodman HVAC system (6 years old) with a downstairs and upstairs zone with automatic dampers. We've been experiencing much lower airflow upstairs recently, and during a routine service/cleaning visit, the tech took a look at it. The damper is opening and closing, but it isn't fully opening (from what I understood from his analysis and the follow up research I've been trying to do). He quoted me a rather exorbitant price for replacing both dampers with a Honeywell system. My question is whether there's anything I can check/do for this damper to verify that it actually isn't opening all the way? If that's the case, is there a solution to that without fully replacing the dampers?

Thank you!

Will H

source https://hvac-talk.com/vbb/threads/2241720-Automatic-Zone-Damper-Question?goto=newpost