Relative positions of layers within the upholstery 'sandwich'

If, as the name implies, the 'hairproof cambric cover' is there to retain the horse/tail/hair, then why in the AB-002 is it beneath the horsetail layer whereas in the other mattresses it's above?
What's the difference between 'bonded' wool & cotton, and 'blended' wool & cotton? and why are their positons in the 'sandwich' reversed in the AB-002 and the AB-004?
Not trying to be awkward, just like to fully understand.
Thanks