Can anyone give a formula in a cell without many arguments in other columns?

I have a spreadsheet for staff provisions like vacation pay, severance pay
and air ticket which I have to update on monthly basis.

For vacation pay, the calculation is like this:

First 5 years. 14 days pay per year and afterwards 21 days per year. So the
calculation goes like this: (Here (in Kuwait) one month is considered as 26
days)

Basic pay/26*14/365*Number of days for the first five years or 1825 days

Later

Basic pay/26*21/365*Number of days after the first five years or 1825 days.

But if a person returns from vacation on completion of 4 years, and goes for
vacation on completion of 6 years, he will get 14 days pay for 5th year and
21 days pay for 6th year. I hope it is clear.

Now I am doing this by putting many arguments like <5 years, 5 years in
helper columns and hiding

I have Bade No., Name, Basic Pay, First Entry, Last Entry in columns: A to
E. I need the formula in Column F.

Can anyone help?

Thanks in advance.

Jaleel