This may be slightly off topic, but I cannot think of a better stack site to put this on so let me know if there is one.

I am using the MAS 500 ERP system's APIs to move invoices into the accounting system. It seems that the API will not process more than 3 invoices at a time. I pull my test data from a table with 9 invoices in it. They all get staged successfully with the same session key, however, when I run the stored proc to put them in the system, only 3 go through. The other 6 do not fail, they simply are not processed at all. I could call the procedure for every invoice(or every 3), but its expensive at about 10 seconds a call. Is there some sort of max on how many invoices can be processed per call? Could it really be only 3? Any other ideas?