Hi bluesteel,
Sorry … I did my calculations on a queen size (60 x 80 x 3) and not a king size so you’re right that my calculations are wrong. Thanks for the correction.
For a king size it would work out to the 3.16 density that you mentioned which isn’t close to the 5.3 lb density that you thought you were ordering.
NOTE ADDED: Because of their ongoing customer service issues and delays their membership has now been terminated and I would read the warning here before considering them.
Phoenix