I understand this has surely been dealt with before, but I seem to be failing to get a full grasp of the concept.

I have had my P3S for almost 5 month now, and for a whole month I didn't fly it, because it was in maintenance at DJI.
Is it normal that my original battery (the very one that came with the drone) is showing 97% of life after a full charge?
Logs say the battery condition is "normal", which I'm glad of, but it seems to me it lost already a lot of juice for about 40 flights in 5 months.

Any comments?

Btw, this morning I was adjusting some settings on the DJI Go App, with drone powered on and motors shut off... and in less than ten minutes it lost 2% more of power getting to 95% while doing almost nothing

Those figures seem good to me, nothing to be concerned about.

Are you confusing charge level with battery life ?

Battery life is like the age of a battery.
If humans live to 80 years, then your battery is 2.4 years old.

I might very well be confusing charge with life, but.... Is the percentage on top of the screen the life expectancy? Don't think so. I expect it to be 100% when full charged.