Ouch. You stepped into one of the pitfalls of buying the no-expiration option. If you need to buy any additional days for a future trip, then it's NEVER a good idea to buy the NE feature.
By today's prices, your 7-day NE hopper cost you $364.50. To buy an additional 2-day hopper for this trip is $188.51, for a total expense of $553.01.
If you'd bought a 6-day EXPIRING hopper last time, it would have cost $269.45. And then buying a 3-day hopper for this trip would be $252.41, for a ttoal expense of $521.86.
Buying the no-expiration option last time was about $31 MORE EXPENSIVE than if you'd bought regular expiring tickets last time AND this time.
Before you go and do the same thing again, do the math first.

But as a short-cut, just remember that if you'll need to buy additional days of admission on a future trip (to add on to the left-over non-expiring days from this trip), then just don't go to the expense of the NE feature because it's just not worth it.
GOOD LUCK!