They didn't provide any numerical comparison. Just said killing boss granted 30% more exp.
You just can't believe anything on Internet.
Maybe running some super lowbie dungeons solo under level 70 job could provide quick results.
I'm grateful for this reply, I genuinely thought something went wrong when I saw that my General chat log wasn't full with EXP additions. Seems better to move it all on the boss. Thanks!
I have been spam leveling Jobs more than doing MSQ and I can testify bosses give more XP with the earring than without. Had a few without the earring in their set so I accidentally did some while lacking the increase. There was a sure difference.