I note that the voltages are NOT adjustable on that unit. They use 14.6 for charging, for example. Better and future proof would be a unit with adjustable voltages
If you buy a current manufactured unit it does drop to 13.6V. I am not sure when the change was made but I bought a second one 4-5 months ago from etrailer and it is working fine and drops to 13.6V once the battery is fully charged. Now I have a 14.6V power supply sitting on the shelf....