Yup, it is the type of silliness, that really frustrated me. If you got 100,000 troops all camped out with 5 miles of railroad station it is actually easier to supply them then, if you have 20K, 40 miles north of the station 20k 20 miles north 20k at the station 20K 20 miles south and 20K 40miles south. But as far as HOI is concerned the 100K at hub will be in poor supply and the troops spread out will be worse.