Have a calculation that provides the results from.

We charge $12,500 on a support contract. If the client goes over 105 hours
we charge an additional $125.00 per hour for the hours over 105 hours. In
this case they had 120 hours in this month. If they are under they still
pay the 12,500


Cell 1 Cell 2
Total Hours Cost

120 =sum(?


What would be the proper calculation.