Requires some luck. You can have a 3-3 week where all games were close except one that was a blow out and that really bolsters you or sinks you. 

Run differential is a good proxy for how good a team is in a season. I am not sure it says much in a given week and since we are picking a new team each week I think it is a lot of luck. 

StackerSports

I think many of my winning weeks still had negative run differentials and my strikes came with truly catastrophic losses.

Undisciplined

Run differential tells me I was barely avoiding strikes with 3-3 weeks 