drifter- companies often times have fixed prices that are considered full price for prepay customers, and fixed prices or full prices for none prepaying customers, the prepay eliminates any credit risk, allows you to have the money now instead of later, eliminates factoring costs etc, but nigerian govts case its not about the financial incentive so much as it is the guarantee of having nicosan available to them eliminating the risk of nicosan demand outweighing the supply and having to wait for more with backorders imo