Well, the reader still uses (standby) power even in sleep. If you want to save battery you have to hard turn off whenever you don't use it (e.g. when you go to sleep). Unfortunately there is no key to turn it off - so the only way to achieve it is set the hard turn off delay to minimum.
With the 1.13 firmware one of the reasons to disable hard turn off is that the reader forgets its book location and selected font size when that happens. In the newer firmware 1.28 I think the reader is able to remember those settings better. I still prefer 1.13 though since 1.28 also added other changes such as a progress bar while you read.
You can upgrade to 1.28, and downgrade to 1.13, with no problem though, so you can just update and see if you like it or not. Just make sure to always use the full firmware files, ignore whatever may be in the patches/ folder if present.
As for battery life in general, I think you are expecting too much. First of all the 7000 does not refer to pages (the way the ADE counts pages) but screen refreshes (every time you press any button); then that's just the optimal case, as in, you continuously press the button until the power runs out.
In reality you are not scrolling through the book but reading, and the reader uses power while you read (it needs to keep the ram populated, and wait for keyboard input, etc.). So while you could probably get 7000 page turns if you just kept pressing the button for 15 minutes, in reality you'll probably do 100 page turns in an hour and the reader just uses a little power in the background all the time.
You should be fine for reading for 2-3 days (unless you read non-stop during a holiday maybe). Just hook up the reader to USB charger whenever you sleep and you should be fine.
Before the Story HD I had a PocketBook 360 and its battery life was about the same. The way I see it it's prefectly normal behaviour, the battery life is still very good compared to smartphones/tablets.