@mattliddle @Fred I discovered an important insight! When powering it through USB (I'm using the expansion board 2.1) there is an LED light that turns on and stays on even in deep sleep. I was measuring current draw and it was always at least 14 mA. I tried powering the device outside of the expansion board by a 3.7V source, and in deep sleep, sure enough it dropped into the microamp range. Even when it is on expansion board 2.1 and powered through battery instead of usb, the LED stays turned off, and therefore power consumption will drop into the micro amp range.