How can we create a project invoice where the quantity field in AR is equal to the hours billed on t

Hello all,

We are using project billing in 12.1.3.  For projects where we are billing for Labor hours, we have created an invoice format that lists the

1) Billing Title

2) Bill Rate

3) Total Hours

When this interfaces to AR, this is then listed in the description field for my AR Invoice Line.  The Quantity for my AR line is listed as 1.

Is there a way to have my AR Invoice line quantity be set as the total hours from projects?  Or is the AR Invoice line always going to be listed as 1?

Thank you,

Lisa