Custom Formula Field Puzzle

Custom Formula Field Puzzle

Business Scenario:

We pay our account managers incentives for every 6 months that they hold an active account.

I have created a formula field that returns the accounts age in months: Datecomp(Now(),${Customers.TKS Signup Date})/(60*24*30)

However, we need a formula field that returns a True or False when the age is evenly divisible by 6.

As a result, when an account age is say 6 or 12 or 18, etc., then we can pay the account owners the incentive per number of accounts that hit the anniversary age.

Can anyone assist with this?