My opinion,
Multiprocessor architecture - save dynamic power, by distributing the computation to several processing cores which is running at lower frequency (than the initial single core). For static power, it using the same library as is the initial single core, it could increase it because we add more processor.
single processor architecture - save static power because you only have single processor. while for the dynamic power, it is difficult to control/manage because we have to deal with the internal (microarchitecture) of the processor (not much can be done when compared with multiprocessor architecture).
Perhaps other members can provide more arguments.
Thanks.