your 8 YOE no NS right. maybe coz the 9k guy got NS, so had initial increment

your 5.8k didnt include bonuses right. maybe coz the 9k guy factored in bonuses

your performance perhaps not as outstanding as his too?

could also be the 9k guy ramped up his salary by a lot when he was in private sector? then switched over mid career with a pay match?

just some logical guesses