Meanwhile I've sent an e-mail to the official ModelOff address and I've got this reply:
[h=2]Re: ModelOff 2015 - % of people getting through the first round[/h]"Thanks for your email. To be honest there's no real set cut-off one way or another. It can be generally be anywhere from Top 40% to Top 60%, depending on how strong people's performances are. We're not in the business of being overly harsh with this - it's more just a need to progress people who are competent enough to handle tougher Round 2 questions."
So, it's pretty much the same as you've mentioned above.
But thank you for the overall score that you provided that should be enough to go through.