okay , thank you for your explanantion , but the real height : is it the morning height or evening height ?
Late morning to evening are what you look to people. I would consider someone's true height to be several hours out of bed since that's when they're seen at, say 0.5 cm above their evening height, not quite fully compressed spine yet. You don't shrink much more after noon compared to within 3 hours of wakening where you lose a significant amount of height and claiming it is ridiculous since it only lasts for a while and isn't how tall you're going to look for the most part.
I'm about 170cm in the morning, solid 169 late morning to early noon and almost 169cm most of the day and can be 168-168.7 at night so I consider myself roughly 5ft 6 ½.
Also why are you even on here at 6'1"? I doubt you would shrink that much so maybe you're not measuring properly anyway. Over an inch is on the very high end of shrinkage even for a moderately tall person, let alone 4 cm.