Has anybody noticed?

Am I dreaming or have others noticed? I try and get as much use as possible from my AA/AAA collection as possible not all but say 3 or 4 of each AA/AAA.I seem to get longer and better run times on AAA rather than AA.Take for example my EDC Itp A3,been used a lot last 2 weeks on high so plonked a fresh cell in tonight to make sure it has food for work tomorrow.Been using a similar lumens AA cell (Itp A2) and have had to put a fresh cell in much quicker but used a little less.



That is one example but has been like that for a while now on my other AA cell lights all of similar lumens levels.