The moment Jon Kent was "born" I thought "replacement Superboy". Kids in comics always have this problem. You can't age them without aging the universe around them each year. And they can never be "older" than the universe around them (Jon can never be twenty as that would put most adult heroes in their fifties). So inevitably they get aged up artificially. Or they're kept young like Bart Simpson, but that makes the universe seem more stagnant for some reason. The designs for LOSH simply confirm he's "permanently" Superboy, even resembling New 52 Superman slightly.