As a firm who helps with PR's weekly, we encounter dealer's claiming to have access to 15%-25% discount from various brands. The net/net to consider:
1) The % off is always relevant to what the "suggested" dealer costing is. For example, a competing manufacturer could raise their dealer costing to in effect, offer a deeper discount than they would have reflected previously.
2) % off can indeed vary by model, whether it is new introduction, a need to move inventory or pending EOL status.
3) Are the models apples-to-apples in comparison, feature wise/warranty/etc. Getting 25% off on a 2MP camera when 5MP is the desired solution as an example.
Another ripple effect is that when an integrator hears another competitor has already secured a PR with such a deep discount, it can motivate them to find another more cost effective brand to compete against that tactic, therefore introducing even more brand options to the end user.