I'm honestly a little confused. Do the plates only protect that given row or column? The manual states that they protect sides - which honestly makes no sense to me because it feels ridiculously overpowered. However, if it only applies to that particular coordinate, then it also seems a little underpowered, as you can easily use your shields + booster to do the same job. Am I missing something?
Indestructible plating protects the tile it's on against damage from the sides it covers. If the damage hits a different tile, or it doesn't come from a protected direction (either because it comes from an unprotected direction, or because it doesn't come from any direction - like sabotage) then the plating does nothing.