As others have said, I think the shop could have done better in explaining the program.
As for the motivation to sell to the gov't at a discount- the manufacturers do this for a couple of reasons.
1. Quantity discount. If a law enforcement agency wants to adopt a sidearm, it will be buying more than if the OP adopts that same sidearm.
2. If a military or law enforcement agency adopts the manufacturer's firearm, it gives the brand credibility in the civilian market. People will even buy ugly, blocky, plastic combat tupperware, if the cops buy them. As a matter of fact, it was one of Glock's biggest selling points.