I am trying to develop an Earned Leave form for my company that each employee
can utilize for his/her own purpose. I need to create a formula for sick
leave. We accrue 8 hours per month on the 16th day of each month.

For example, I would like to create a formula for "Jane Doe". She began
working on August 1, 2007. On August 16th, the formula adds 8 hours to
Jane's Sick Leave balance. On September 16, it adds an additional 8 hours
for a total of 16 hours of Sick Leave balance, etc. On October 27th, Jane
will be out of the office on sick leave for 3 hours. In another cell, she
will post the 3 hours. In the first cell where the formula is calculating
the 8 hour accruals, Jane can also request the that the formula also subtract
any value posted the second cell. Therefore, Jane's total Sick Leave balance
as showing in the cell would be 21 hours of sick leave remaining (8 hours on
August 16th, 8 hours on September 16th, 8 hours on october 16th, minus 3
hours on October 27th).

If this makes sense to anyone, I would greatly appreciate ascertaining if
this is possible. Thank you.