I think that part of the reason for this precept was that high and luxurious seating has pretty much always existed for the sole purpose of setting the seated personage above those around them (often literally as well as figuratively), and that there is attachment in this kind of luxury.
If you examine our most ancient notions about royalty and power, you will find that these are very often associated with some ornate or large furniture. Etymologically, we say the "seat" of power, for example.
I think that, when attempting to practice this precept at home, ask yourself: "what are my desires and intentions in owning this or that bed or chair? Do I seek to set myself above others, to project my opulence and status in any small way? Is the purpose of this furniture strictly functional, or is it decorated and flourished to convey said opulence and status in any way? Do I feel that I deserve this luxury?" I think, in the answers to these questions (and bearing the Middle Way in mind), you will be able to determine whether you are breaking this precept for yourself.