The idea is to try and push them to minnow in 1 month. It will take a ton of coordinated efforts to get someone from 400 to 500sp in a month, but trying to help them grow 300sp would be nearly impossible.
It also show a level of commitment making it to 400sp IMO.
Now mind you these aren't @pifc's rules, we are working with others who started this initiative. But we do fully understand why they picked the levels they did.