The real problem is the reliance on timed standardized testing in the first place. One way or another, undue attention gets focused on improving test scores, and the more $$$ a family has to invest in that project, the higher the likelihood of achieving a high score. Which in turn renders the tests pretty much meaningless in terms of providing any sort of info about ability or achievement for scores at the upper end of the range.
But then again, if the colleges are using the scores as a way of shaping the economic profile of their incoming class in order to ensure a steady influx of full-pay students… then the disparities serve to enhance the value of that test as a tool for favoring students whose parents are able to pay for four years of college.