All - I will do my best to describe what I am trying to do here (and striking out). I have poured over this forum and I find examples that are close, but I can't find the silver bullet. Hopefully one of you talented folks can help.

I have an array that looks as so.

Start Date|Class size|Est Term 1|Est Term 2|Est Term 3|Est Term 4|Est Term 5|Est Term 6|Est Term 7|Est Term 8|Est Term 9 etc...
6/15/2013 8 7/20/2013 7/20/2013 4/5/2014 11/2/2013 10/11/2014 7/26/2014 3/14/2015 6/13/2015
9/14/2013 7 9/28/2013 10/12/2013 5/17/2014 2/21/2015 2/15/2014 7/11/2015 9/5/2015
12/14/2013 8 1/11/2014 1/4/2014 5/31/2014 8/16/2014 10/11/2014 1/31/2015 11/14/2015 9/19/2015
3/1/2014 10 3/15/2014 3/22/2014 3/29/2014 8/2/2014 7/4/2015 9/6/2014 10/11/2014 10/31/2015 11/28/2015

Start date (A) is the date that the class starts and each "est term" date (C:N) is when we predict they will leave or transition to a new roll.

The table I need to fill out with this array looks like so.
Date 0-56 57-126 127-245 246+
7/1/2013 counts counts counts counts
8/1/2013 counts counts
9/1/2013
10/1/2013
11/1/2013
12/1/2013
1/1/2014

For each of the "counts" cells I need to know how many employees I will have on that date in each range. The ranges are number of days they have been with the company. I can use sumif just fine and get the number of employees in the buckets, but I can't seem to back out the employees who have terminated.

Please let me know how you would attack this. Thank you guys in advance for helping!