I would be testing entirely differently for phantom draw. Bike off, remove positive cable, insert multimeter set for dc current (ideally low value current less than 1A, not 10A range) between removed cables and positive. Ideally number would be zero but if it's not, note the number. Reinstall cables and pull fuses one at a time. Multimeter set the same way, probes on each leg of the fuse socket. Should be zero, look for one that's not (ideally one is close to your noted number). Once you have found the circuit that is acting up, Look for where the power could be going (split plugs if possible to narrow down the location as if current stops when you split a plug, you know the draw is after the plug).
EDIT:
Start with amp meter in aftermarket usb line, then do the above.