Does Sonia have a ton of HP and DEF and low ATK all because of Impregnable, her unique skill? Shouldn't they have the same MP because they're the same level? I guess it wouldn't be exactly the same if level stats are decided randomly.
In DQ3 if you level down, it takes around 20 days to catch up to the rest of your party. I feel like for the sake of the story Loa catches up much quicker than normal.