See examples given above that three different major programs are openly planning to back count early enrollment kids for this class and we did it ourselves in 2005. Some pretty brazen cheating if it's not allowed.I don't think you can back count. What you can do is sign a Juco and have him enroll first semester and count him in that year's total. So if you had 25 LOI's in Feb and 2 didn't qualify, you could have 2 Juco's sign in the fall and have them count towards that year's total.
My impression is that you can play the juco game or do grayshirts to help shift counts from 1 year to the next to meet the 15 limit, but the overall limit of 75 is the limit that's hard to work around.
Agree though that the 75/85 limit is typically the real limiting factor. Even that can be worked around with med schollies and running kids off, which seems rampant in the sec.