Hi Ron,
In support we always recommend having Multicurrency enabled for anyone on GP 2013 and higher just because we only test functionality and new features with MC enabled and we don't see many cases where it's not enabled any more.
(+) Multicurrency Management: Should I enable it? - Microsoft Dynamics GP Community
In your case it may not be required, but in generally I just wanted to recommend it.
With Web Services we only hit the taMCCurrencyValidate procedure if it finds a mismatch between the currency id on the transaction and the currency id on the company for functional currency.
1. I would make sure that the Currency ID and the Currency Index in the MC40000 match the Currency ID and Currency Index in the MC40200 for Z-US$.
select FUNLCURR,FUNCRIDX,* from COMPANY..MC40000
select CURNCYID,CURRNIDX,* from DYNAMNICS..MC40200
2. I would pass in the Z-US$ currency on your Receivables transactions coming in from Web Services so that it can find a match right away and not have to use additional logic such as looking at the Customer ID in the RM00101 for the currency id and falling back to the MC40000 to pull the functional.
I hope this helps! Web Services would have also required a Functional Currency when it was installed, so if they changed that after the install for Management Reporter, maybe Web Services needs to be reinstalled to pick up the change too.
Isaac Olson
Microsoft Support
