If you really want to help the Sub, and the Cable company is acting Bitch, then disco the dish box right before the appt, then after the appt add the diaplexer. Ive done this many times, and yes it can make your return on that hsi modem a little borderline (high) but it works just fine.
This is CABL.com posting #259250. Tiny Link: cabl.co/mbfBC