Some questions I can choose Most Helpful after an hour of asking, but others it says it's too soon. I posted a question yesterday and I tried picking Most Helpful but it said too soon for Most Helpful. Today I posted a question, and I was able to pick Most Helpful after two hours.
Does it have to do with the amount of answers?
Most Helpful Girl
To pick a MHO quickly, a minimum of 4 opinions is needed.
If you get 4 opinions in a short amount of time (2 minutes or so), the system will allow you to select. Otherwise, the system makes you wait a day or two in the hopes that you'll receive more responses.2