No the moca devices should control the band [usually a software setting of switch on the device] but you do need a filter that covers that band typically in a "I use comcast,/charter/rogers environment" they run up to 1ghz or plan to, so you use the D band which is like 1002 Mhz and above them but you cannot be feeding it to their plant, so the filter is applied to the ground block or first splitter to prevent that also supposed to help reflect signal back to you and improve your moca but I have never seen that actually happen.
However, if you are getting the same speed directly out of the modem, like bill is talking about you have a problem before the Moca. Do you know what your upload speed actually is, I know the company I work for has an old package that ended up being 1G down and 5 Mb up, which is just illogical but its there, you may need to verify the sold speed for your package.