Good video, this really shows that it doesn't work as a deadener.
Even with 2 to 3-4 layers you didn't get decent deadening.
And like kandiman said, HD doesn't sell deadener, only people who don't know whar or how a deadener work say that roofing products are deadeners.
You would get better 'deadener' by just using spray foam in the trunk, but thats just me