Dean Jones says:

"That's some movement in the right direction...

Here's my counter-offer:

You are required to teach Two summer sessions, neither of which count toward your teaching load; each class will hold 80% more students as the normal summer session.

Your response:

1.  I will accept that offer.

2.  I will accept -- provided that you limit the number of extra students in my summer classes to 40%.

3.  I won't go above 35% extra students.