Import Cost: Ability to add a fixed amount to a cost for a specific expenditure type

We have a requirement to add a fixed amount to the worker cost when the time reported in the timecard is against a specific Expenditure Type.

Ex:

TIME TYPE | MONDAY | TUESDAY | WEDNESDAY | THURSDAY | FRIDAY

Regular | 8 | 6 | 8 | 8 | 5

Prem | | 2 | | | 3

After the import cost process we would expect:

• Regular time (35 Hours) to be billed with the standard cost of the worker
• Prem time (5) to be billed with standard cost of the worker + a fixed per hours

Is this something achievable through configuration or custom formula (Or else)

Thanks