Didn't you post this on bb.com this morning? Anywho, I'll answer similar to what I did over there...
Prices always drop after a while. New products are always more expensive due to them being new, testing the marketplace, and unfamiliar popularity. As it becomes popular, wildly so in the case of SX, prices usually drop. From a business standpoint (retailers), lower prices but more units sold equals higher profit yield. In the beginning, the risk of a new product at a higher price yields profit, but is an unknown due to the virginity of the product. Once established, the price can literally "afford" to drop.
The serving size for SX is going to remain the same. Despite what you see from forum members here, the dose of 1/day is good for the vast majority of users (most of which never see a forum). At that dose, a bottle lasts quite a while and is a bargain at almost any price. For us seasoned big guys who are used to needing a bit more, it's still a good deal considering the effectiveness of the product. Heck, at a lower price, buy 2!!
Different version? Hmmm.... it'd be logical to have a milder one for the stim-insensitive and household lady audience, right? Yeah, I think that'd make sense. If you want stronger, I hear there's a guy in the alley behind the 7-11 who may be able to help you out with that. It's cash only, so hit the MAC machine first.