I have been working with a Firestorm dev on this issue, he has pretty much sorted out the repeats per meter not working at all, but...

Now he has the ui working, there is a disconnect from the Blinn-phong in that with BP textures the repeats per meter uses the texture aspect ratio for repeating, as you would expect.

The PBR repeats per meter is using the objects aspect ratio and changes the texture to match that and repeat.

Not only is this for the majority of cases not the expected behaviour given most textures are 1:1 ratio and designed to be repeated AT that ratio, it is also a complete disconnect from the BP and PBR workflows where the same UI elements will produce different repeats.