Prognocis Assessment has a provision of assigning one or more Modifiers to each CPT Code. Please Note, these are not assigned to HCPC codes. These codes influence the variance in charges to be considered. Group Master Type CM has a provision to define the modifier codes, along with applicable percentage.

If percentage is 0, it is treated as 100%. If a Provider is assisting another Provider, he will use one of the modifiers, in his Bill. The rate then applicable / charged will be factored by this percentage. If more than one modifier is used, it will be a progressive reduction.
e.g. CPT Code say 10560 has U&C Rate of $1000
Modifier 80 has an associated value of 20 percent.
Effective rate for 10560 with Modifier 80 = 20% of $1000 = $200

Modifier 51 has an associated value of 50 percent. If both modifiers are used, then Effective rate for 10560 with Modifier 80 and 51 = 50% of (20% of $1000) = 50% of ($200) = $100

The rate will be flat Dollar for some modifier codes like TC Technical Charges and 26 Professional Charges for Interpretation (like reading a CT scan) The list of these modifiers is defined as a comma separated list in the property,
Billing > fee.fixrate.modifiers
Please Note that the Program still prompts for percentage even for these codes, but the calculation does not consider the value entered here.