sounds like they saying depends on the size of your order you might not get s.t.p. it might not reach the banks.
I actually just talked to them. Yes, the one trading platform is for the Retail base (FX next) and trading on currenex is for the more savvy investor. It doesn't matter the size, it will get filled but maybe not all at the price you want (you'll get that WMA price) so it's a risk. That is where platforms like flextrade comeinto play.