if I count, the first whole number is 1 so 1,2,3 is acceptable. If am doing placeholding 0 is the starting point 0,1,2,3 this does matter when designing according to bellcore standards. Went 2 weeks discovering the SS7 congestion messages were being kicked 1,2,3 on one end and 0,1,2 on the other, it took a while for the A-links to sync.
thanx,
bill