Formula to work out Leave days due

Hi all
I am trying to work out the formulas for leave days due from start date, with columns:
Employee Code
Employee Name
Department Code
Date Employed
Date Terminated
Monthly Salary
Leave Entitlement
Opening Leave Day
Leave Accrued
Leave Days Taken
Leave Days Paid
Leave Days Due
Leave Provision
No.of years since start date and today

I have the formula for leave accrued if 2015 (=ROUNDUP(1.25*ROUND(12-MONTH(D6),G2),0)) but can't do the formula if the year is 2010 or 2014 for instance. Our company does not carry over leave or increase leave with the years. Everyone gets 15 days maximum each year.

Please can you assist?

Thanks
Robyn

A small sample file with clear explanation of the "leave day" rules will help to get a response. What is the particular problem with 2010 and 2014?.