Why hyphen is used to number section 194-I, 194-IA, 194-IB, 194-IC and 115-O

Almost in all other sections of the Income Tax Act,1961 hyphen is not used to number the sections except 194-I, 194-IA, 194-IB, 194-IC and 115-O

Anyone know the reason?

Though this not much important, just curious to know the history behind this "-"(Hyphen)