Seems interesting - what is the average price psqf?

Only worry is what happens if this cellulose comes in contact with water? E.g. From a leaking roof, from a leaking tank, etc.
Most of this are unnoticed because the celllose is actually insulating the water from the ceiling, which will be hidden from you unless you go into the roof and check. Will it expand? Disintegrate, or grow mold (hazard ot health)?

Did you have wall insulations as well?

I think you're looking for this - Residential roofing with fiberglass.

http://www.unitedseasons.com/acco.html

Sound and heat insulation. Roof tilting can be minimal which is normally suitable for single story extensions (e.g. Kitchen).
In comparison to using roof tiles you need quite a high angle tilt to prevent rain water leakage.