I dont think its right, from personal experience, one of our players got a 5 match additional suspension and due to us having weeks off and christmas etc, he missed about 6 or 7 Saturday games as well. In addition to this, when our first team had the week off, we asked if he could play for the ressies, we were told no, so we asked if this meant that it counted towards his suspension and it didnt.
I would say that if you are doing match based, then do it to cover Saturday and Sundays, but, include the caveat that they must have played 75% of the games for their Saturday team (which stops players signing on Saturdays to reduce suspensions).
Our player stomped off with the arse and didnt give his name, and as a result, he missed about 12 additional games including Fri and Sat...crazy amounts really considering Wayne Rooney can tell a ref to 'fu@k off' and not even get a booking!!
Also, whilst on a moan, i think the video evidence thing is rubbish as well, unable to appeal a red card unless you have video evidence! We have had a sending off this season that even County FA said shouldnt have been a sending off based upon the refs report, but because we had no video evidence, nothing could be done!! Stupid rule...oh, and take a video camera down a park, and you probably have to get permission in case their are kids walking around...its a ridiculous rule in my opinion