Hey there,

our Argents reached the throne argent status and for the ascension psychic powers there is a special rule that i can forget a minor or major power to lower the price of the rank 2 and 3. But if i have 10 powers of one disciplin and then forget one of that major powers do i lose the disciplin mastery? 'cos i want to forget fling and telekinesis for the psychokinesis powers.

i would think that yes you will lose the mastery, as it is required to have the required 10.