You can change the LSB in styles using MixMaster. Go to the Multi Processing Menu (choose batch process) and you will see Change LSB for Normal Voices and Drum kits. You must know the current LSB used in the styles and what the LSB is in your expansion pack.
This is useful if you already have used the pack Voices for other styles. If you change the LSB in the pack and re-install, then you may have the same problem with other styles not playing correctly.
Another approach is to add those styles to the expansion pack and re-install the pack. You can do this by using Import Content (the styles) and adding them to the pack. That way the styles will have the correct LSB.
Joe H