Well, five threads in a twelve-thread system is 41.7%. Five Primegrid processes at 8% is 40%. I don't see much discrepancy.
My Ubuntu system says [process monitor] 48% usage for SR5 running 4 threads, [resource monitor] sees eight threads active at 50% on average. Resource monitor is really dynamic, switching threads from core to core, but I believe that is what it is trying to tell me.