https://forums.daybreakgames.com/eq/...-to-do.229581/
This is one of the biggest things missing from EQEmu's melee code. AFAIK this is basically how it worked during velious as well, the main thing being that players simply didn't have high enough attack to really see the maxextra being hit. Also at launch of velious everyone was at 210 but monks who were at 220. In a patch in September of 2001 (before luclin) they revamped that code a bit giving melees of 51+ a higher melee table and monks even higher.
The attack (calc isn't shown) in that snippet is based on the return from the offense function AFAIK, which may or may not be further modified. There is also an entry condition that is missing from this snippet since it is possible to hit for weapon_damage / 10, Torven has parsed this condition to be ~115 (notice there is a min extra of 10 and the default minusfactor is 105, so possible is correct) offense. The chance which also isn't used is a roll to not add in the extra damage AFAIK, since it is still possible to hit for weapon_damage / 10 with offense > 115. (if your offense is less than 115 you actually hit like an NPC for 20 different values :P)
I'm not 100% sure what the damage table values were after that September patch during velious, I do know the 210 and 220 points are correct and the patch notes make it sound like melees moved to 220 and monks moved to higher 51+, but that's not what this code is doing.