Unless I'm missing something it could be same as earnings code for OT that uses multiplier 1.5.  If it is not regular or overtime hours, use Miscellaneous.  Call it Pay Rate 2, then select Miscellaneous, Standard, Pay Rate 1 and 1.50 Pay Rate Multiplier.  That would have hours field available but you could just enter manually calculated amount if hours does not apply.

Unless I'm missing something it could be same as earnings code for OT that uses multiplier 1.5.  If it is not regular or overtime hours, use Miscellaneous.  Call it Pay Rate 2, then select Miscellaneous, Standard, Pay Rate 1 and 1.50 Pay Rate Multiplier.  That would have hours field available but you could just enter manually calculated amount if hours does not apply.