That looks like the last time the Job has been billed, not a billing date filter.  If you want that, filter based on the transaction table's date value (InvoiceDate?), not something from JC_Job.

I'm pulling the amount (InvoiceBilled) from the JC_JobBillingHistory table, but there's no date range in this table?

That is a summary table and there is a fiscal year / period in that table which you could use.

I don't know JC files at all, but if the summary data doesn't suffice, perhaps look in JC_JobHistoryTransDetail for billing detail / Invoice amounts.

Ha! One would think that file would have the information...but it's an empty file.