InfoPath Dev

I am trying to put together a calculation.....

1.  I have a field called Devices (whole number)
   
2. I have a field called Users (whole number)
3. i have a field for the calculation that will charge users * $50
   

 my NEW calculation needs to figure if the number of devices is GREATER ">" than the number of users by more than a multiplier of 3, then run the calculation of "$60".

 Can someone please tell me the calculation for this???

anybody have any ideas on this please??

I'm sure I have way more parenthesis than mathematically necessary here, but I'd use something like:

my:Users * ((60 * ((my:Devices div 3) > my:Users)) + (50 * ((my:Devices div 3) <= my:Users)))