LogFAQs > #971109070

Second Sealed Rosado to give him Swords instead of Lances, went back to promoted level 1 from 7, with no effect on his stats. Looks like there really is no downside whatsoever to second sealing whenever you want. Also means people were right when they said you should just promote at 10 if you can and not wait.

I think (still need to confirm) the only limitation here other than the seals in your inventory/money to buy them is that you can't seal back to level 1 in the same advanced class until you cap it out?