vt730: vtws_retrieve of Opportunity doesn't handle currency conversion

If I have a user on vtiger that has a currency which is not the default currency, when that user creates an Opportunity, the "Amount" field is saved in the database with its value converted to the default currency.

When, as that user, I view my opportunity on-screen, the value is converted back to my default currency.

When I use the REST or Server API retrieve method, the value is returned as the converted value, not as my default currency value.

There are two possible solutions to this I can see.

1. Fix vtws_retrieve to return the converted value (but if it's a different user calling vtws_retrieve and they use a different currency to the user that created the Opportunity??? What then?)

2. Add the currency type picklist field (currency_id) to the Opportunity. This seems a better solution to me as there may be users who want to create Opportunities that are in different currencies anyway... Perhaps, any module where currency fields are used or added, this should be automatic?