2 level mesh V-Core 4 - 400 - IDEX

Dears, I am puzzled from this bed mesh on a V-Core 4 400 IDEX. I don't know where to start because of this odd shape, on the Y axis I think... I found no similar references. Could you please point me on the right direction? P.S.: I assembled the printer on a granite surface, good flatness but not perfect, with an engineering square. Plus, all the screws of the linear rails tight the same force with a Dynamometric screwdriver, per specs. Thank you! Daryl.