I agree. If your aircon was damaged, it would leak refrigerant immediately and there would be instantaneously no cooling. It there is a big delay between the hit and the loss of cooling, the problem lies elsewhere. I feel the same, that was a stone hit and Honda needs to put in a guard to protect it. As a rule, if the ASS
is quoting a large bill for the work, go to a trusted mechanic and have it checked. ASS
simply have a replace policy. So if a part is not working, even if its a small issue, they will replace and ask you to foot the bill.
By the way, don't doubt the size of the refrigerant piping. Aircon pipes are thin to begin with because the amount of refrigerant they carry is so small. They are also copper pipes, so they are very soft and can be bent by hand. Check the pipes in your household AC if you want. They are soft and so can take a lot of vibrations without breaking. A impact from a stone, however, is a different matter