Set number of decimals for each currency seperatly

I think we are one of the few companies in the Japanese market using XTRF, but we really would like to have a system-side solution for this. The problem with Japanese Yen is that no decimals are being used. There is no 0.1 yen. (Only in stock markets). Therefore, all invoices, POs, quotes need to be rounded to 1 yen. This is difficult when introducing percentage rates for CAT tools. This will almost always result in a decimal on the total. We have had a solution where only the templates would show rounded totals, but this keeps biting us in the ... We can have rounded total on 1 quote, but the system will store the amounts with decimals. So when we invoice for multiple quotes, the invoice totals will sometimes be different from the total amount of the rounded totals on the quotes. This is giving us some trouble with clients, since they have to go back and forth with their financial departments to correct this 1 yen mistakes.

I do understand there is an option to change the number of decimals in the system, but this is system wide. Since we do projects in USD and EUR as well, this is not really an option. Therefore, it would be really helpful if there was an extra setting for the currencies where we can select the amount of decimals for each currency separately. I am guessing there are some other currencies with the same issue (probably Korean Won and others).

We have been told some of this could be solved with a macro, but I think the above solution would work best.

Either way, I am happy to hear if there are people with similar problems.