Hi Tom,
I guess that is why it’s called “draft”! 
Probably so that as much as possible will be aligned in the shortest possible time.
I encountered that as well, that the max repro error is not adhered to 100%. But it’s rare enough. Keep your total features in mind though when you go down with the setting - the number will decrease rapidly and there might be areas where you won’t have any left, so check the model thoroughly before you continue. I have tried once and got the best results (in my case) with 1.5 error.