Andrew is much more powerful and strong Moguior but he is not able to control that power like his twin brother so he has a disadvantage.
As for Moguior, he may be weaker but if he knows how to use his energy, power and strength efficiently because he could easily beat Andrew in battle.
the difference in powers in fusion that balances out, taking moguiandr to another level.
If they fight as a team without fusion, they would be a very difficult duo to beat.