Your source of info is correct in many cases. The shocks on many RV's have to be mounted at such an angle, that it renders their function near useless. You may feel in your mind the near horizontal mount factory shocks improve your RV's ride, but if you saw how little the shock actually moves in a normal bump situation you may tend to agree with me. The add-on shocks available out there with mounting brackets and all are way more vertical and do contribute to ride control.
http://www.rvimprovementsystems.com/