sorry for the math fail there, but lets say a 5'8 guy compared to a 5'10 guy, i have noticed that the difference between them seem to be bigger in overall size compared to when i have seen 5'10 guys standing next to 6'0 guys.
THe reason i think is because after a certain height threshold, the rest of the body parts dont get much bigger in size, or at least not to the same degree as it does for people between 160-170 cm.
For example, most 5'10 guys i have seen tend to have similar size heads to people who are around 6'0, of course with some exceptions. while at 5'8 or below, they always seem to have significantly smaller hands and heads etc, shorter arms.
im generalizing but in my opinion this tends to be the norm.
Lol it's all good man. You do bring up a good point that the shorter 5'8ers sometimes have smaller bodies so the difference from 5'8 to 5'10 may seem larger than 5'10 to 6'0 but I also think it has to do with their height in relation to the average . For example when I wear 1 inch lifts and go to clubs at 5'8 I feel and look small if I were to take a picture of myself, because the average people around me seem to be about 5'10. However when I put on boots I put together to take myself from 5'7 to 5'11, I look relatively tallish because my head is a bit higher than most.
Going from 5'8 to 5'10 brings your eye level and head to about where everyone else is at so it seems to be a big deal, whereas 5'10 to 6'0 is icing on top as now you are above average height people and may occasionally be called tall, though my opinion is that solid tall starts at 6'1 but that is off topic and that number is completely debatable depending on the average height of where you live.
Cheers my friend.