The Aruch HaShulchan tries to reconcile the Shach who holds that Milsa d’Avida l’Ta’ama is d’Rabannan and the Kreisi u’Pleisi who holds it is d”Oraisa. He differentiates between the slight flavor generally added by spices, which is Ta’am Kalush when less than 1/60 and d’Rabannan and a dominat flavor that would be d’Oraisa.
He certainly holds that Ta’am Kalush could apply to Avida l’Ta’ama.