Benjamin,
I wanted to thank you for making this plugin. It's working perfectly for me. I've noticed people wanting location updates more frequently than 15 minutes. I did as well, since I'm mainly using it to set my thermostat to "Away" if my wife and I are both more than 7 miles from home, and then turn that off if we're closer. At the 15 minute update interval we could be home by the time the thermostat status updated, so the house would still be warm.
I saw your posts about Apple caching the location data. Well if they were doing that before, they don't seem to be doing it now. I went into the Find My iDevices! preferences file, and changed it to update once a minute, and it is updating everything every minute with no problem. The location, charging status and charge level are all being updated consistently every single time it runs. I've had it this way for over a week now, and I can see my wife driving down the highway updating in real time every minute.
One thing of note is that I'm running iOS8 Beta 2, but I don't think that matters since my wife is still on iOS7.
I would donate some money, but I didn't see a link to do so. I'll also probably email you about a custom plugin I might be interested in.