Typically these days it seems to be less desirable drugs
substituted for cocaine
to turn a bigger profit and stretch dealer supply. Caffeine
for example, but also camfetamine mixed with dimethocaine
sometimes for legit taste and feel and just about any other edgy stimulant without a quick high and comedown
Your theory may also have something to it, but 1g lines are absurd... your coke
must be badly cut IMO. Huge lines like that are called "gaggers" by some for the numbing effect they have on the throat and swallowing reflex, leading to the potential for more than gagging, like choking/vomiting party tricks.
Perhaps more time between redosing will allow the effect to remain somewhat through time. Think of how great each line will feel after 40-50 minutes, that's not impossible if you are somewhat occupied and maybe having a few beers or what have you.