So I'm obviously out of touch but I can see $126k being upper-middle. in my head there are 6 classes. lower, lower-middle, middle, upper-middle, upper, ultra rich. and, again this is just in my head if you asked me, "hey sd, if my household income (2 adults) was X where would you say I fell?" I would make the cutoffs:
lower: below $25k
lower-middle: $25k-$50k
middle: $50k-$100k
upper-middle: $100k-$250k
upper: $250k-$1 million
ultra rich: $1 million+ or a net worth of $5 million+
but, without anything to describe the classes other than the words that make up the class names it's pretty meaningless. also net worth isn't something I think about outside of the ultra rich and it probably should be.