Surgeon become a mechanic

Northern CA
A Surgeon got tired of all the stress from dealing with lawyers, HMOs and nutzoid patients, so he decided to become mechanic. He closed his practice and enrolled in a 6 month mechanics school. The Doctor did remarkably well in his classes, and was looking forward to graduating when he took his final. He felt pretty good about how he did on the valve job that had to be completed in 4 hours, might have even aced it. The next day thay came to class and the instructor handed out certificates to those who passed and words of condolance to those who failed. The good doctor was the last to be called up in front of the class. The instructor handed him his final completion certificate and the first prize certificate. Ali looked at the certifcate and it said Grade = 200%. He told the instructor that he appreciated the grade but didn't understand how it was possible to get 200% when 100% was perfect. The instructor told Ali that the first 100% was for the perfect valve job, the second 100% was for doing it through the tailpipe while the engine was running [Cheers!]