How Does Scorn Earth Interact with Listen and Move Silently?

The Elocater Prestige Class has the supernatural ability Scorn Earth [Expanded Psionics Handbook, p.143]

From now on, she can float a foot above the ground. Instead of walking she glides along, unconcerned with the hard earth or difficult terrain. While she remains within 1 foot of a flat surface of any solid or liquid, she can take normal actions and make normal attacks, and can move at her normal speed (she can even “run” at four times her normal speed). However, at distances higher than 1 foot above any surface, her speed diminishes to 10 feet per round. While she remains within 1 foot of a surface, she can make melee and ranged attacks normally, but if she moves any higher, she incurs the penalties on melee and ranged attack rolls as if she were the subject of the psionic levitate [p.114] power (see the levitate spell description, page 248 of the Player’s Handbook).

Since the character would be out of contact with the ground, and is unaffected by difficult terrain, is there any benefit to his Move Silently checks, or penalty to other characters' Listen checks to hear him moving in this way?

Is there any difference for stealthy movement between his moving while within 1 foot of a surface and his movement while greater than 1 foot above a surface?

This ability is not a fly speed as in this other question… but are the answers the same?

Move Silently says

Noisy surfaces, such as bogs or undergrowth, are tough to move silently across. When you try to sneak across such a surface, you take a penalty on your Move Silently check as indicated below.

Surface	Check Modifier
Noisy (scree, shallow or deep bog, undergrowth, dense rubble)	-2
Very noisy (dense undergrowth, deep snow)	-5

This is not related to difficult terrain or not, it is based on wether the surface is noisy or not.

When you floating across the surface and above the features that cause the noise, I think it is safe to assume that you would not be affected by the negative modifiers. It will be up to your DM for each individual case to determine how high above the surface these features extend, and therfore, if they affect you or not.

For example, if I were your DM, I might rule that "undergrowth" or "dense undergrowth" is not part of the "flat surface" of the ground you are hovering across, but it is what makes you have difficulty moving silently there, and if it is higher than 1 foot, then you will suffer a penalty, as leaves still can rustle and twigs snap. Whereas, bog (if there are nor high reeds) or deep snow creates its own flat surface (and to note, the ability also allows you to hover over water), so I would rule that you would hover 1 foot above the bog or snow, not the ground underneath, and therefore would not be affected by the penalty. But for all these special situations, there are no in-detail rules, so you will have to rely on the judgement of your DM to resolve it case-by-case.

I think the same would apply to fly, but there of course you can more easily just fly high enough to avoid the terrain.