When using different currencies with similar names, Koha should advert that you can't add currency names with spaces in them. This result in later not being able to add orders. For example, defining currencies like "PESO ARG", "PESO BOL", "PESO CHILE", etc. result in the mentioned problem to not be able to add orders in the acquisition module. Koha should advert that currency names should be entered without spaces.
I think maybe we should fix the behavior instead. It looks like something with the JavaScript on this page is going wrong. When you modify an existing order and change the currency to one with a space, the form shows a lot of NaN instead of the calculated values.