720M=7 wrong, but 650M=8 wrong?!? please help!

For what it’s worth, I checked out the scoring guides from Collegeboard’s practice tests. For a 50/58, the score would be 700, 720, 710, 750, 710, 710, 690, 740 in order form tests 1-8. Considering that even their tests range in difficulty and the lowest score they award is a 690, a 650 seems low to me…