The Skiller can decide whether he wants to give up to 5 minutes free. Its good in order to check if they match. And in case that the 5 minutes free was enough for the whole service the user can tip the Skiller and everyone will be happy

How do you prevent people from abusing this 5 minute grace period?
Thats why i would like to see some kind of comments for users too,where Skillers could see such a thing.So for example if user often abuse this thing,other Skillers would be able to see that and simply reject the call and save the time.