The growth on the custom parameter plugin is the same effect that Item has on the database. Below the item will have an effect to increase + 10 on the max hp.
For the custom parameter, you can add the note tag set on the help file also to increase their values.
With only the custom parameter plugin, you can increase their values with script calls and plugin commands or equipment. So if you change the level, use the script/plugin commands provided in the help file.
Another way to make them increase on each level is using the Class Curves plugin.