Starting Phase 1 of getting to the ultima weapon with an issue

I joined my first 8 man dungeon as a 50 PLD as i join now there are 2 tanks granted this wasn't a hard fight. Everyone there was in agreement that one tank kept boss the other went after adds along with DPS. My issue was that the other tank was like ill be main you go after adds but adds dont spawn till 50%. I pulled more hate without using flash or provoke i was just attacking and he was also a pld so when doing so should tanks compare stats to see who should be main and secondary or am i in the wrong which i have no problem with just didnt quite understand it.

Well u can always hold back in your hate generation, if u guys decide that one will be main and the other will off tank just don't use the hate generation abilities so often, fights can go really wrong if the tanks start to fight over who will be main and who will be offtank. Also IMHO main tanking is usually less demanding than off tank in 8 man dungeons, so if u consider yourself better geared u should probably go for the offtank position.