[Invoice] Project billing by percent completion of tasks

Hello,

I appreciate the various options for Project billing types and budgeting found in Zoho Invoice, but I would like to either propose a new method or find out if it' s currently possible.

It would be very helpful to have project tasks that have a budget item (lump sum), against which the client is billed according to a percent completion of the task. This percent completion would not be tied to time logged or task billing rates.

Here's an example:

Project X total budget = $10,000

Task A total budget $5,000

Task B total budget $5,000

The first invoice to the client might include partial completion of the tasks, and so billing would be:

Task A

Percent Complete = 50%

Amount Billed This Invoice = $2,500

Budget Remaining = $2,500

Task B

Percent Complete = 0

Amount billed = 0

Budget Remaining = $5,000

This is pretty standard for construction and other projects where tasks may be budgeted for a lump sum and not time and materials (hourly rate). Ideally, I would like to be able to use percentages and remaining balances for task level budgets, but at the least, it would be nice to have tasks with a lump sum budget option and projects that can be billed by task budget but not require assignment of hourly rates or staff time.

Thank you!