Hi Carl,
For situations like this we've always bought the DLU's in bulk
like you nicely noted and then charged back the proportionate
amount to the Department.
So if we bought 100 DLU's @ x $$ (say $5,000)
We would charge the cost of the 7937 + 3/100 of the $5,000
Cheers!
Rob
"And if I should fall behind
Wait for me" - Springsteen