In fact, here are the numbers:

Metro MO comprises four counties-Jackson, Clay, Platte and Cass- population 994,759

Metro KS comprises two counties-Johnson, Wyandotte-population 608,968

This is from 2000 Census, and is the only official number to use. When you leave these counties geogrpahically, then you get a larger number of smaller schools, so adding Douglas Co and Shawnee Co in KS only equalizes the population. That is why the rules are what they are.