I wish you would be able to put in a custom amount. All of your amounts that we have to pick from do not equal or come close to the amounts in the add ons or top up choices. I have to do to two transactions every month. I wish you could pick your account type from the add ons and click pay from credit card and that is the amount you can pay, not have to do 2 transactions to top up account and then find your add on that you want.
Is this something you will eventually change.. this has been an issue for as long as i can remember.
When you change the rates you need to change the option type top ups, as there is nothing that equals the top up amounts.