Regarding Item's leveling mechanism.

Roughly 4-5m exp was 18% on my Overall (currently level 1 (starting level)). I forgot I was wearing it or I would've had more specific numbers.

Hm, going by Fiel's KMST thread from a year ago (and the relatively bad assumption that the system hasn't been changed since then):

리버스 타라곤
Warrior only - Longcoat
Req Level: 120
Req STR: 370
WDEF: +196
STR: +8
DEX: +7
ACC: +3

Level-up system
EXP Table: 70 --> 75 --> 80 --> 0
Bonuses each level: STR(0-1), DEX(0-1), Avoid(1-2)

You have a 1 in 10 chance of getting a skill at level 4
Possible skills: Achilles +1

18% of 70 is 12.6
Check:
12/70 ~= 17.1% (can't be)
13/70 ~= 18.6% (must be)

So your overall has 13/70 experience on it.

Seems like a 1:350000 scale, approximately...