Neither is completely true.
Mythical sockets take mythical armor power into consideration and set bonus's as well as the enviroment they are intended for.
I don't want them being mandatory 2x the power because there is only half the slots. Half the slots is because of a bug with TL2 and MP. Its the only reason there is 2, of course because of it I made mythical socketables a lot more readily accessible. tier1.5 sockets were never found even a fraction as much as these ones.
Tier1 socketables will be an increase form tier0 where the same stats existed between the two sets.
Where I made them from scratch I do want them to be stronger then any unique versions, hence if I was off on how much they offer, please speak up.