Time Accounting in E1 9.0. Using Pay Code with pay source 'F' - Fixed Price does NOT work?

Using Time Accounting (only) in E1 9.0, defined a Pay Code with pay source 'F' - Fixed Price.  I would expect the Amount (in the units field) to flow through to the Timecard with NO other amount fields populated.  Found that the employee's distribution rate use used to calculate the amount field.  This flows through to Service Billing indicating a Cost that's not required.

Anyone using Time Accounting with this requirement?

If so how have you worked around this?

FURTHER COMMENTS

We are using the Occupational Pay Rates (Distribution Rate) and works fine for all our Pay Types.

We've defined a Pay Code with pay source' F' where we record the "Fixed Amount" to bill (per work order) in the F06116.YTPHRW field which flows through to Service Billing.