Indian prefold unbleached cloth diapers ????

I HAVE planned to order indian unbleached cloth diapers but i need to know how does the differnce in size 'preemie,infant and premium' really matters as i can see there is no such size diffence in Gerber prefolds cloth diaper .I was thinking that it is just to make more money when moms will order dozens of diapers at diffent satges..Has anyone ever used both infant and premuim size and think that premium can be be suitable for infant..thanks