It seems I'm too dumb to set this up.
I have a support project with a flat, monthly fee for resource allocation, and a hourly rate for tending to support requests. We have agreed that the first billable 1.5 hours will be included in the monthly fee.
I use timers to track time spent on each support request. I use a separate timer for each support request (title will e.g. be "Bug 5678"). That will round up the measured time as per my configured rounding granularity, and create billable work items accordingly. So far so good.
Is there any setup, in which the first 1.5 hours (after rounding up) get created as work items with a zero rate?
I guess the fallback would be to create the invoice, and then manually edit the work item rates to get the desired effect. But what if one timer had accumulated more than 1.5 hours? How can I retroactively set the rate for only part of the clocked hours?
Any hints appreciated!