Because then they need to file the pricing with ICASA etc ... Basically by running pricing as promotions they manage to circumvent all sorts of regulations (not sure which but look at consumer protection, interconnect. USAF contributions and minimum service). Think of promotional pricing as the "norm" as similar to labour brokers - a reaction to a failing regulatory system. IIRC the pricing that is regular pricing must remain the same for a year. Telkom now has to get approval from ICASA on their tariff proposal even though a lot of their coming to the party hasn't worked its way into the tariff - - meaning that either promotional announcements will be coming or ICASA won't accept the tariffs (which really isn't ideal)