The calculation is not quite as simple as it initially might look. Scores of the weaker students will improve more than those of stronger students, because weaker students will miss more questions and thus fail to be penalized for "guessing" more often. And free response scores will not go up, only multiple choice. This all points to adding a bit to each score cutoff, with more being added to the lower cutoffs.
This year, I'm going to use these cutoffs in my class. I'll see if they work... and I'll appreciate feedback, as well:
We'll only know more through experience, and when another released exam comes out.