This^^^^^^^^AASPs have metrics they have to maintain such as parts per repair and first time fix, which affects their compensation for warranty repairs. Because of this the techs usually take their time to verify your issue instead of just throwing parts at it.
When I worked for Apple as a Genius we constantly had machines come back after the first repair because it wasn't actually fixed. I now work for a Premium level AASP (because I left working for Apple due to this and another reasons) and our repeat rate over the last year has been 0. I believe our quality of work is much better. Also, if you go to an AASP you are usually supporting a small business.