Music Power Scroll are in demand due to every bard need the music skill even if they only use one other bardic skill, not so much with Scroll of Transcendence. Musicianship is the base... BUT it is gain through use and checked on each and every skill use as well insturment use. IMO ,You will be hard pressed to get anywhere close to your asking price.
The best prices are got from skills that use ALOT of resources ( Smithing ) or time a major amount of time to get gains(Taming ).
Music is sort of like eval,arms lore,anatomy,tacts.. Gains are consistant and worked during all game play..