Total Job Cost needs to equal Cost in GL

NAV 2009 R2.

Using the job costing module in NAV, recording my usage, and contract and schedule lines.

If I post usage, I can run the WIP and post to GL, it will record my cost in the GL. So my cost in the Job Cost module and GL are the same.

What if I post a purchase invoice, code it to a job, and post it. Now I have the expense in the GL. But now if i run my WIP again, it will include this new usage cost and post it to the GL. Now I have just doubled up my cost haven’t i ?

I am drawing a blank here…thanks.

The goal is to have my job cost in the job module and GL be the same.

Just as a side note…the same goes for payroll. I do a journal entry in NAV for My payroll, so it hits the gl. But I will also enter this resource in the job journal and post it since they worked on a job. Now if I post WIP, won’t it double up my cost’s in the GL ?

Regarding Payroll & resource how are you paying them double payment.

An person can be on payroll or can be resource and not the both.

I will post the journal entry for payroll.

DR salaries

CR Bank.

Now i will post this resource in the job journal too since he worked on the job.

Now if I run WIP, the job costs (including his payroll) will hit a job costing GL account.

So the GL gets hit twice with the payroll expense.

Or is that what it is supposed to do. The first entry is the GL amount, and the second is the job costing amount ?