Fields accessed by the Formula f(x) button
Clicking the Formula f(x) button displays the Expression Editor window.
This window allows you to create variable billing rates by attaching a user-defined formula to the rate. When a formula rate is applied to an order, the system pulls the user-defined data from the database, and then it uses this data to apply a calculated rate to the order.
Formulas can be based on these elements:
Operators
Addition, subtraction, multiplication, division, and parentheses.
Parameters
Billable miles, count, index factor (allows indexes on the same rate to have different factors), minimum quantity, rate (linked to the Rate field or a rate table), volume, weight.
Numbers
Whole numbers or decimal numbers.
Formulas can be attached to simple rates, which have single per-unit amounts, or to table rates.
For details, see Applying user-defined formulas to billing rates.