Before you go deleting all your sound regions, there is a simpler fix for the region problem (this applies to
all regions), it helps to understand what's going wrong.
When you resize the region in object mode, it simply gets some 'scaling' attributes, but the mesh stays the same. Since regions are apparently not scaled during export, or in plasma, the actual region is seen by the engine at it's original size. You can identify such objects by checking their properties for scaling. Simply press N with an object selected, or menus > Object > Transform Properties, to bring up the transform properties dialog (which I see you have up in your screenshots), which shows the global location, rotation, and scaling, of an object. If the "Scale" or "Rot" properties are anything besides one, for Scale, and zero for Rot, that region doesn't look like you think it does.
To fix existing regions like this, simply select such an object in object mode and press Ctrl+A, or go to the menus > Object > Clear/Apply > Apply Scale/Rotation. The object will not appear to change, but all of it's scaling and rotation will be applied directly to the mesh.
Also, I generally set friction "rc" to 10.000, otherwise I slide around a lot, and it's rather disconcerting.

And finally, you can view multiple layers at once if you hold shift while selecting them. (no need for double screenshots)
(I just noticed that BobLishman mentioned the apply scale/rot method (briefly) in his post... I don't know why that didn't work for you. It has for me.)