Every job got 2% chance of dropping EC. You can try first 3 jobs as i've heard they drop EC very easily.
1st job , 3rd job n the job frosh week which is further down in the jobs with the 7k payout. helped me change names 4-5 times already n goin for 6th
No job drops more than another, ALL jobs have a 2% CHANCE of dropping. First job is only recommended due to that it has an almost 100% success rate and uses minimal energy, increasing number of times you can do it, and more times you do it more chance you might get that lucky 2%