Airpods Max battery consumption while in Smart Case

Context: Airpods Max, with latest firmware, put in their Smart Case to rest.

On the support page How to charge your AirPods Max and learn about battery life (yes, I read it, so please do not mention it in your replies), Apple explains that APM should go into low power mode instantly, and into ultra-low power mode after 18 hours.

In the last few days I checked my APM battery before going to sleep, and in the morning (~8 hours later, so no ultra-low power mode involved) I found that the battery consumption is 6-7% overnight.

I also had them rest in the Smart Case for nearly 48h hours (so both low + ultra-low power modes), and the overall battery consumption when I picked them up again was 9%.

What's your experience in similar conditions? I searched a lot online and someone reported 2-3% overnight, others 10%. Just wondering what an 'average' might be here.

To be thorough, I always used APM with iPhone, and disconnected as expected when being put in Smart Case (checked on battery widget).