Looking at this from gameplay and job quest perspective I feel the earliest they could implement it would be maybe around level 60 but not via summoning but through pseudo-trances. As in reworking the animation of using your egi/demi into trance, allowing the option to use Impulse for new effect and ending it after we spend both charges/run out of time. Thematically it would tie with the latest power up from story perspective while adding part of benefits from demis