Your mother is not US citizen? or green card holder yet you could pick it as LVO. I don't doubt your reply but this seems impossible as from what I read that you need to pick home country only. So far, you were approved and no issues? I am tempted to ask around again as this would have been better
I mean, so many parents have US visit visa, it would have been better to pick US as LVO, has anyone heard about this setup before
Also, you managed to get extensions for 4 years? 6+6+...continuous, vow that's something too. I can understand 3 or 4 max, but thats a lot! What reasons did you give
BTW, what nationality are you -- can you share your timeline etc