I have been considering the mx-500 to replace my Harmony remote. Overall the Harmony works ok but has anyone who owns a Harmony have any issues with the volume going out of control. I'll just try to raise the volume a few notches (pressing only a couple of times) and it will max out the volume on the 990. It will do the same when trying to lower the volume. Is that flaw just a Harmony trait or will the MX do it as well.