If you want to be more accurate, plugged your numbers into my simple Excel thing I made...(538,000/57) x 116 + 700 = 1,094,900.
The only problem there, Mike, is that the points from deaths are contributing to the stage average for Levels 1-11 (assuming 3 deaths occurred during Levels 9-11, with the final one coming on L12-1). Also, did you intend to divide 538k by 57, or 56?
Since I don't know the start, I'll ignore it, and I'll assume an average of 5000 points per death in the 2 examples below.
1) Using Mike's "average per screen" approach gets us very close to 1.1 million:
Pace = 116 x (( 538000 - 15000 ) / 56 ) + 15000 + 700 = 1,099,100
2) Weighting Levels 9 through 11 more heavily gives us a higher pace:
Pace = 538000 + (( 538000 - 346200 - 15000 ) / ( 11 - 8 )) x ( 21 - 11 ) + 700 = 1,128,000
Either way, you had a possible 1.1 million point game in progress.