[Field Service].Status Reason for Invoice (Work Order)

Dear all Pros,

It says Billed on the form, but in the grid (list of invoice) it says New ? I don't know why 

And how to change status reason for Invoice (WO) to Billed ?

The way to billed WO: 
I change System Status in WO to Close-Posted, then the system automation generate to invoice, I do not interfere anything.

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