I'm looking to get my garage attic insulated and they told me that there is 11 grades of insulation.?

Question:It goes from Grade 1 (the lowest rated) all the way up to grade 11 (the best - highest rated)

They told me for my garage which is a standard 2 car garage, the space in the attic above the garage (which is what I need to insulate) will cost anywhere from $200 for the lowest rated insulation all the way up to about $1600 for the highest rated insulation. He told me that the minimum recommended for a Florida house is Grade 9 which is about $1200 to insulate the garage attic. He told me that on average, the average basic insulation loses about 10% every year with the insulation being useless after about 10 years. He said that if I go with the Grade 9 or higher, it comes with a life-time warranty - guarantee and that it should never falter. Is this all a bunch of BULL or is insulation a thing with a lot of variables??

Answers:
I've been an insulation installer for the last 25 yrs. I've never heard insulation refered to in grades. Insulation is measured in inches & r values. There are two types of insulation I would recomend cellulose or fiber glass . Althoe, I lean more tward cellulose which sould be inslalled with 8% water to presettle the insulation, plus bind the fibers together. the water has no ill afects on the dry wall . By the way cellulose is lose fill blown in. R-30 in fla. is more than fine. R-30 cell. is 8.5 inches & R-30 fiber glass is 11to12 in. I would call another insulation co. I'm sorry the sales man you talked to is full of crap! Insulation will not lose it's R-value if its installed properly. Can I have that guys number so I can read to him from the book of morals?