precise meaning of PML_x

[matthuszagh]

The openems BC page says the following about PML:

PML_x: Perfectly Matched Layer absorbing boundary condition, using x number of cells

I took this to mean x cells are part of the PML (which I think is correct) but it could be intended to mean x mesh lines are part of the PML. If this is the case I've taken one more mesh line than necessary to be part of the boundary. This should be verified in the forum.