They did change the salary structure in the first two months which was a bit disingenuous on their part but I understand too they are trying to build a new business model for themselves.
The system of fighting for the 20 top tutor positions is flawed, you need to reply to an email twice a week within 30 seconds to secure the hourly rate, if you don't get it you are relegated to a per class payment where there is no guarantee. You can't control how fast an email comes to you or returns to the server you are sending it to. I feel cheated when I don't get in.
They pay well and on time, but there is no clarity in the salary, there is no information available on the hours you worked . If you are mixing the hourly rate and the per class work it would be a nightmare to understand.