Recently we revised our on page ranking signals. We then thought it a good idea to revise some keywords for attributed PPC campaigns. We accidentally removed one keyword and then re-added it, only to find that the quality score had jumped for a 6 to a 10. Nice! We thought it might be a good idea to delete and re-input keywords to see if their QS changed, they actually all did. 90% of them went to a QS of 10. We actually went through each keyword deleting and replacing and getting the same results.. After coming back to the account (and after emailing my boss with 'win win!') the QSs had returned to normal. What is Google playing at?