Yes. Previously when it showed 0.4% it was actually more. It is a bug with the bq27x00_battery module, some software then reports incorrect battery percentage. So you could do so much with 0.4% before because it was more (maybe 10%? maybe even 15%) and then when it showed 0.4% in the second situation, it might really be 0.4%. It is bug known to power kernel dev (devs?), because it was reported and discussed in power kernel thread earlier. It will be probably fixed somehow in future power kernel releases.