I would seriously like to know how your insulation guy would add insulation to the valted area of your CYV??
I am 98.876% sure it was built using a scissor truss which makes it virtually impossible (at anything resembling a reasonable cost) to retro fit additional insulation in that area ... as their is simply no room, way to access the area or needed dead space to add the insulation.
Scissors truss - Wikipedia, the free encyclopedia