Replacing IF function with VBA

Hi all,

I am putting together a spreadsheet to track equipment and would like to remove the "IF" function that is used in column N due to nested restrictions.

I've searched the forum but can't seem to find a VBA that suits, or is easily deciphered by a newbie like me.

Is there a VBA that would achieve this, i.e. =IF(B5=$Q$5,M5+1095, IF(B5=$Q$6,M5+730, IF(B5=$Q$7,M5+730, IF(B5=$Q$8,M5+1825, IF(B5=$Q$9,M5+1825, IF(B5=$Q$10,M5+182, IF(B5=$Q$11,M5+730, IF(B5=$Q$12,M5+730)))))))) and still allow to addition items to be added to column Q?

The +X in the formula above relates to "Test date due" frequency which varies depending on equipment.

Any advise would be greatly appreciated.

Grant