Since there is no official database I try to figure out is there any experiece penalty in case characters in party has different level.
I've found table https://l2classic.club/forum/topic/17989-guide-experience-exp-and-skill-points-sp-edited-10052019/ in section "Penalty Experience and Skill points (SP)"
And example in text:
Is it correct for our "classic" server? Or there is another rules?