I emailed Joe Harkins at Installs Inc. I asked him a basic question regarding what customers are being told (up to 4 lines of coax) and what installers are told about one line of coax using the diplexer. This is Joe's response.
We are reworking our scope of work to reflect two changes. We did not have the VOOM provided multi-switch for 3 room and above jobs. We are also working on language to make the installers understand that they can either use a diplexer or run a separate line as determined by the individual needs of the job.
They are not supposed to charge for the extra line.