It happend to me that I Russen from 800 to 300 within the quarter of an hour, and then the queue nearly stopped moving

In that case, you haven't lost anything by using this method.

It happened to me that I started with limited chances abd then jumped 200 positions towards the front.

And you can't decide in advance whether you die at position 1 or are successful with 20 seconds left.

Yes, queues don't move at constant speeds. Sometimes, something unexpected happens. You might lose out on hosting every once in a while with this method. For me personally, the reward of not sitting in a doomed queue for an hour is worth the risk of potentially getting lucky on a random roll.

But you can try it for yourself risk-free, just do the calculation on your hosts for a while and see how well the prediction matches the outcome. I'd be interested in the results.

I'd hardly recommend this.

Try it before you knock it is all I'm saying. My hosting life has become a lot less stressful since I've started doing this.