planar textures on cut surfaces

I am experimenting with making texture sheets for a little cottage I am building. I have found a good way to start is to cover the prims with the builder's grid texture, planar, 1 repeat/metre in both directions to measure the surfaces to be covered.

Today, I am texturing some kitchen cabinets and follow the usual routine, but cannot get the textures to align correctly with 1 repeat/metre on all surfaces. The top flat surface and the long, hollow surface behave as expected, but to get the end cut surfaces right I have to use a repeat of 1.42/metre in each direction.



Is there something odd about cut surfaces that I am not taking into account, or is this some sort of glitch? I'm on Emerald, if that makes a difference. It's not a huge problem, as I can just squish the finished texture to fit, but it made me curious.

ETA: Just to be clear, this is one prim, cut and hollowed.