Quoted $7K for replacing evaporator coil on Lennox heat pump...Too much or is that the typical cost?

I have a Lennox CBX26UH-036-230-1 heat pump that services two zones on a 1700 Sq Ft unit. We started seeing the temperature go up on both zones in early afternoon, despite the unit working non-stop. The tech came and did his diagnostics, and ended up adding ~4 lbs of refrigerant, which I expected based on my readings from this sub. They mentioned that replacing the coil (which is most likely where the leak is) should be around $2.5K, but then I got the emailed quote from the company at $7K and change.

I understand there is overhead and the company needs to make a profit, but this seems excessive. Based on a quick search, I can find "Lennox 12W73 Evaporator Coil" for sale ranging from 1.8k-2.6K, so the markup for the installation seems unreasonably high.

Am I missing something here like this part being extremely difficult to install? It doesn't seem like it is rare to procure, which was my original suspicion. I'd appreciate any advice.