I have a Helix 15 SI at the Bow connected to M360 and Ultrex MDI transducer via Y cable. I find I don't use 2D or MDI up front, so was thinking of disabling the pinging of those sonars by selecting only M360 as the connected transducer in the sonar menu, instead of including the built-in transducer as I now have it. Am I correct in assuming that the Helix will then only ping the M360 ?