That's weird. I just tested it and it does update in the background when the battery saving option is unchecked.

Make sure the checkbox is not ticked and select 7 minutes as the update interval. Close the program, open it back, wait for the first update which begins 10 seconds after the app is started; when its done notice the "Last Update" date. Now, send the app to the background and check back in 7 or 8 minutes and notice the last update date.

It's important to notice that if you press the Back button, the app will be closed. To send the app to the background press the red (hang up) button (default behavior).

Let me know how it goes.