First off, the $xx off of $xxx sales are usually not the best deals. Canon's refurb store usually inflates the asking price a bit before these sales. It is the xx% off deals that are the best. They don't always inflate the asking price before these. Either way, they are just marketing to their crowd. Most people have no idea there is such a thing as a Canon refurb store, or they do and they just don't want refurbs. Everybody continues to sell full price new gear when the refurb store is undercutting them. Ebay continues to sell used gear when the refurb store is undercutting the listing/auction prices.
I complained about the stocking games, but now that canonpricewatch has added a stock tracker, I'm more interested in playing the game. To get a good deal on a refurb, you basically have to watch the stock and sales over time, set a notification at your price threshold, and hope to get lucky. It sounds like you bought it at a price that you were happy with. The only places I've ever heard of giving refunds for a later sale are the big boys, and only on the new gear.
I say all of this having NOT bought a 6D at the miraculously low zombie sale price in October (for various reasons). Now, every time I look at the current price, I weigh it against that price, but it may literally never be that low again. That's the game, and I lost, because I didn't have the cash on hand then.