i disagree. giving orders to mercenary bands is actually quite near to what we know of the time. there were no soldiers as we now have back then. every man had his loyality directly to his leader who was responsible for recruting him.
knights would have knaves to their command and would, if neccessary, recruite local people and/or mercanaries when they got called to arms.
AFAIK, typical mercenary contaract would give mercenary leaders payment for a specified number of troops with specified equipement and specified expirience. such a contract was usually acountable only for a season and would also specify shares in loot, bonuses and appropriate behaviour and treatment.
the mercenary leader would pay the sold out of the capital he got from the contractor and out of his own and his business partners investments in the undertaking. then have a contract with the mercenary, which would also specify reparations for injuries and widdows' rent. it was all quite commercial and well sorted out back then.