Yeah, mom is also far below my percentage. I need to see about getting into the Choctaw tribe.
I presumably have a higher percentage as well.
But, consider it like citizenship. If your mother is one citizenship and your father is another, are you 'half-citizens' of each country? No, you're either a citizen or you're not.
In the interests of racial purity or some such, if you have sufficient descent from the tribe, they'll let you back in without much hassle. Otherwise, well, as long as their family has kept that membership card going, it doesn't matter how low the percentage goes.
And as Mill mentions, Native Americans aren't above petty politics, though my understanding is that they were mostly disenrolling 'inactive' members who weren't living on the reservation, didn't attend tribal meetings, etc...