Thanks for the feedback. Much appreciated. Slow appearance of calculation is something we cannot speed up (not at the moment at least). We are checking rates on several exchanges and choosing between them and different patches to get the customer most valuable exchange rate. Also sometimes exchange's APIs are not too much responsive. I hope to change it as we will send out several partnership proposals so we might get some better API access or so. The link is fixed now.
I see, that's nice.
I know this is a just a little feature but, I'd still suggest that you add something like a placeholder loading icon which will give a hint for users that the converted value will be shown.
It would also be helpful for users who have trouble connecting to your servers. Good luck!