When you use a Payroll Class in a bid, a copy of that Payroll Class is made just for that Bid. This isolates the bid-level record from changes in the Master, other Bids, and vice-versa.
You can use the "Refresh Payroll Wages" option in the Bid menu to pull down the latest pricing from the Master into any Bid.
Master Payroll Class Record
From the Master list, click Change to open the Payroll Class Detail (Master) - notice the word "Master" in the title bar. This means we are editting the Master-level Payroll Class. When a Payroll Class is used in a Bid, a copy is created for that Bid to isolate changes made to it from the Master.
Bid-level Payroll Class Record
When a Payroll Class is used in a Bid, a Bid-Level copy of that Payroll Class is made, notice the Bid name in the title bar. Open this Bid-level record from the Payroll Tab. Change made to a Bid-level Payroll Class record do not affect the Master or any other Bids in the database.