Changing currency problem

Hi .. First of all Thanks for this awesome plugin

I have faced a problem .. that the plugin is programmed to deal only with the default currency format

So if u have any other plugin that switches the currency .. It still deal with numbers as if threy were in the default currency form

For eg: i set the settings to take a 3 % fee of the total cost .. And perhaps the total cost is 50 .. (Using a currency switch) assume that the total cost in the currency B Equals 5000 .. So when it take a 3 % from this total there will be a huge difference