I'm confused, MP40W will not sync with a MP40WES. The boxes don't even look the same. Now a MP40ES will not pair up with a MP40WES either, but the boxes look the same. On my MP10ES the box has the cutout for the W but it is not lite up, the MP10WES has a blue light shinning through the W.
If both of your boxes look the same and only one has a W lite, then thats your answer. One is a MP40ES and One is a W