It wasn't a 300 crown increase on this bundle. It was a discount overall on both sets.
The newer bundle is one in-game style and three artistic styles.
The prior bundle was one in-game style, two artistic styles, and a blank.
Probably thinking most people would want both sets, the newer one is 3 artistic at 250 crowns apiece (750) and one in-game at 200 crowns. That would be 950, but bumped up to 1000 because the Murkmire sub **50 isn't in effect yet.
The prior one was two artistic at 250 apiece (500) and one in-game at 200. 700 total. You get the blank one for free which makes up for the price rounding on the newer set.
I know that per-item costing isn't always apparent when you look at the release order alone. That's why I never assume prices based on the release schedule.
They do this a lot. Then when they want to get rid of stuff it goes on half price etc, etc.. patience can pay off.
It is all just data. ZOS does not have a warehouse full of inventory they need to move.
I would take the interpretation that the "stuff" that they need to get rid of is Crowns held by players. People respond to sales as well as limited time offers.