So why didn't bethesda make dawnguard cost the same price as an actual microsoft points card that stores actually sell.
You mean why doesn't Microsoft sell cards that are worth the same price as actual DLC being released? Answer: To make money.
1400 pts is $17.50. Now, who the hell releases a DLC for $17.50, or any smaller denomination of that? Nobody. This way you are forced to buy either two 1400, or a 2800, and thus microsoft get's your money.
It's the exact same reason everything in stores is 9.99, instead of 10.00. It looks like it's not as much so people are more apt to spend their money. It's a simple marketing ploy to get you to spend more.
It's Microsoft not Bethesda.



. Or raise Canada's from 1400 to 1600.