My apologies for not responding sooner. I do not have the ability to respond from my workplace; I respond when I have spare time at home.
One other thing to look into for current draw is the micro SD card slot. Some micro SD cards consume a lot of power when the card is being accessed. If you are storing data to your memory card frequently, then you may have a higher current draw than you expect.
Are you successfully shutting off the GPS? That looks pretty straight-forward now that you figured out how it should work.
I also want to comment on the general design of Carloop. It was designed to be always on when the car is supplying 12V to the OBDII port. The assumption, which seems to hold true for the majority of cars, is that the 12V to the OBDII port is only ON when the key is in the ignition; sometimes to the accessory position or sometimes only when in the run position. Given that design assumption, the power regulator on the Carloop works nicely with noisy power, but is not necessarily the most efficient.
One final note is that car batteries are not designed for deep cycling; they are not meant to be drained down. The batteries are designed to provide a whole lot of current quickly, which is what is needed to start the engine. If your battery is still functional but on the weak side, then drawing a deeper cycle might mean it can no longer provide starting current from a partially drained state. If nothing else works, maybe get your battery load tested.
Let us know if you get it sorted out or you need further help!