I too use Green Power app in my Android device, but it has never shown such problem. It's working fine in my device.
Are you using cm11 by chance?
I've not had any issues until cm11. It works at times, other times it doesn't. Most times it just doesn't turn off the data/3g.
I always test to see if it's working because I know this test has always worked, and still does WHEN it works. I use a lock pattern. I set green power to no-delay on wake and sleep, so it should happen instant no data on wake and sleep.
If it's working correctly I hit the power button to make the phone sleep, count 1001, 1002, then I check to see if it's disabled or not. If it is working correctly the 3g icon will be gone...which means it's working correctly. In most cases it never disappears at all....even after letting it set an hour long with the screen off, the 3g icon is still there when I check it an hour later.....this means it's not working correctly, which results in battery drain. I got a max of between 6-8 hours yesterday and this was with light to moderate use of the phone, when normally if it's working correctly, I'd get almost 10-12 hours......a pretty significant difference I'd say. Mind you this is not an exact science at all, so the numbers may be slightly off, but it's a general thing....I get almost 1/4 more usage out of the battery if I turn the 3g off on a regular basis.
I realize I can toggle it via the pull down, but I always forget to turn it on again when I am going online for anything, so after a few times it becomes an annoyance because I always forget.....that's why I was looking for a auto toggle app...if possible.
I always check things manually anyways, so having something to auto check I never set anyways, so nothing ever goes out and auto checks for anything, namely because I always disable that part of the app. That's really the ONLY part of these apps such as juice defender and green power, that I use at all.....I never use the wifi disable or apps settings withing the program....I never overclock or mess with cpu settings, and I always turn off the auto check features of the apps. So it really just boils down to I need an app that will toggle 3g/data when I put the phone to sleep/turn the screen off.
I've tried a few out there from store but they also have the same issue. I lean towards 1: the app hasn't been updated to the newer KitKat and/or 2: the app just doesn't wanna work in Kitkat.
I found one that does seem to work and I'm still testing it out, and that's DS Battery Saver (Deep Sleep Battery Saver). So far it's worked correctly. I just put it on last night so I haven't had time to really give it a good testing, but from what I've messed with it a bit it does work with no issues.
I only had this issue in cm11 so far.
I also have gps/bluetooth and everything else toggle related turned off to save power, and I also do not use live wallpapers. So everything is turned off, yet it still does not turn off the 3g data.
UPDATE:
I am currently at 40% after 12hrs now. So it's a go!
Got at least 4 more hours with 25% more left over than I did before so I could probably stretch around a couple 3 hours more being a total of 7-8 hours more time and grand total of 15-17 hours in all.
Nice improvement over what it was before.
Thanks boathead for the suggestion. Best of all its a free solution B-)