Call it a sale, Instant Rebate or just perhaps I am not greedy discount.
In all seriousness, if you feel it is a scam or something shady.. please don't buy it because I find it just insulting. I have had two goals, great software and under the price of a book, I like to think I have accomplished both. I did just recently remove the part on the site that broke down the pricing because all it did was cause my wife to ask me, when is it going to 20? If you are married then I am sure you can understand what I am talking about.
As for Silver and Gold, really depends upon what you desire and your needs. We have had a few Silver sales but all switched to Gold pretty fast and we currently have none at the moment under that license. If you have any questions feel free to ask here or on my forums.