How can we improve WHMCS?

I'm not from US and we are using a different currency as our main/local curency for billing invoices. The main problem is some of the product like the DigiCert in Marketplace is cost and markup is based on USD which we want the currency conversion to be based on USD to local currency. How about our other product and service that are based on our local currency, we want it in the reverse where the local currency will be converted to USD instead of from USD.

For example:
Currency:
USD = 1
PHP = 50

Product
DigiCert ($) = $10 (P500)
IT Service (P) = P1000 ($20)
Other Service (P) = P500 ($10) checked to specify not affected by currency conversion automatic update

Then we change the currency forex to
USD = 50
PHP = 100

The new pricing should be
DigiCert ($) = $10 (P1000)
IT Service (P) = P1000 ($10)
Other Service (P) = P500 ($10)

This wasn't a problem before since the currency forex was stable and no need to update it thru automated conversion. But now we have a very unstable forex the can change rapidly.