A wireless communication transmitter configured to transmit a multi-carrier signal, the multi-carrier signal being an aggregation of two or more separately modulated carriers occupying distinct frequency regions is operated by obtaining a baseline multi-carrier metric indicative of an amount by which a multi-carrier signal's maximum transmit power should be reduced from a pre-determined nominal maximum to satisfy a predetermined out-of-band emission requirement when different scrambling codes are used on all carriers that are combined to create the multi-carrier signal. A compensating metric adjustment value that compensates for an estimation error that results from use of a same scrambling code on two or more of the carriers is estimated. A final multi-carrier metric is obtained by adjusting the baseline metric by an amount based on the compensating metric adjustment value when the same scrambling code is used on the two or more of the carriers.