Strangely, I've observed the same behaviour with people on the exact opposite side of the spectrum too (i.e. UHNW).

A friend of mine worked on superyachts which were £400k a week to rent. He said that without fail the owners would be penny pinching at the end over a few £ here and there (on food, drink, suncream etc.) Same with upper-class Brits who had hundreds of years of intergenerational wealth but won't turn their heating on until November.

Not sure what to make of this; I've often wondered if it is a form of bell curve.