Not exactly an accomplishment, but I thought it was a silly average:
8.75, 10.08, 8.14, 10.00, 8.24, 10.63, 8.70, 10.44, 8.06
Just 8s and 10s, back and forth
I laugh at the 8.70 because I had a free block for x-cross and figured the pattern would continue. :P
Then I finally got 8.52, 854, and...