With that information, the question is this...is it steering wheel position or is it nozzle position? Most of your steering adjustment will be at the nozzles. Your going to have to take measurements and see where your wheel is centered, and if you have full range motion left and right, and is it symmetrical. Meaning, do the nozzles turn left the same distance from center that they do to the right. The hard part is this, adjusting the wheel or the nozzles, will not change what may be causing a drag to need off center thrust. Several guys in the past have discovered that their ride plate was on the boat at an angle and causing a list. Check the two ride plates for being symmetrical too. And as
@itsdgm mentions, you have twin engines and the impellers are not counterrotating, so you have forces at play that Yamaha has attempted to counter with different pitch impellers. If you feel certain that it is off, then your options are to let the dealer take a look at it, or start troubleshooting. While it is common on a jet boat to have to counter forces more dramatically in wheel position, it isn't common that they are off center when it comes to zero force control. It isn't likely, but you could have the wrong pitch impeller installed in one pump or the other...or both.