Yeap, that's pretty much what they mean by fixed time trading, yet, Olymp allows early exits which makes it more of a spread betting or CFDs trading.
I don't think anyone can suggest something better than MT4 for forex and CFDs trading. I don't insist for sure (moreover the choice if probably done already), but if Olymp suggests MT4 to use, that's an excellent option to take advantage of. Yes, the interface might seem to be a little annoying in the beginning, yet the stability of the platform is unbeatable so far. I'm a little surprised though that Olymp has offered MT4, brokers having their own trading software rarely give a chance to use the third party software.