Data in Collapsed table but not Base table

Hi. Why are there some indicators that are available in Collapsed (C) tables, but not in Base (B) tables? I'm looking specifically at C21007: AGE BY VETERAN STATUS BY POVERTY STATUS IN THE PAST 12 MONTHS BY DISABILITY STATUS FOR THE CIVILIAN POPULATION 18 YEARS AND OVER; I'm interested in data on veteran poverty status. This data doesn't seem to be available in any Base table.

Thanks!