How do you upgrade to pro account ?
This will be as easy as possible. Pay indicated amount of BTC to your address and your account will upgrade automatically.
Why BTC? Because there is no easy "forward founds" REST API for LTC. To my knowledge, such API is provided only by blockchain.
ok but there are other services that offer taking payment with other coins
have alook at this site
https://www.coinpayments.net/i have used it a few times with out any problems and it will be better for script miners
as they might not have BTC to pay but they will have other coins.