QBO cannot determine how profitable a specific scope is if you pay piece rate

We are a construction company that installs the windows, mirrors and shower doors. We pay piece rate. This means our installers pay depend on how many items they installed. This means their hourly rate can vary between days and jobs. Right now, QBO CANNOT determine how profitable a specific item is on a profit and loss. Let me walk you through why: 

We record labor in payroll inaccurately making the P&L inaccurate.

Q: Why do we record labor inaccurately? And how do we do it?
A: (Part 1) Because we cannot allocate multiple items in labor for payroll
A: (Part 2) We have to do a lump sum during payroll, where we pay the total amount, without any nuance of what job or item they worked on.

Q: Why can't we allocate multiple items to labor in payroll?
A: Because we cannot use the weekly timesheet function in QBO

Q: Why can't you use the weekly timesheet function in QBO?
A: Because we cannot adjust the hourly rate in QBO. It does not have this function.

SO, to get accurate reports...
- QBO either needs to allow hourly rates to be adjusted OR
- We switch from paying piece to paying hourly (*If weekly timesheets records into the P&L)

One of these two would allow us to use the weekly timesheets function in QBO. Which would allow us to record labor accurately. Which would allow us to determine how profitable a specific item is.

QBO, ADD A WAY TO ALLOW HOURLY RATES TO BE ADJUSTED ON WEEKLY TIMESHEETS PLEASE.