swa66 - 3:06 pm on Nov 12, 2012 (gmt 0)
(((ThisYear - BaseYear) + 12) + (BaseYear - 1))
is mathematically equivalent to
ThisYear + 11
What worries me a lot more is
while still allowing past dates retrieved from the database to be displayed
You do know that storing credit card details is not the right thing to do unless you adhere to the PCI regulations ?