Hiring costs differing between the two.

Hi,

What i was focusing on when doing the case was if the hiring costs would be different between referrals and non-referral candidates. I was expecting the costs of referrals being lower (not taking into account the referral bonus cost) due to marketing costs for recruiting being lower, but maybe this is too negligible? Either way it would have been more clear if it stated that hiring cost would be the same for the referral (excluding bonus), since it makes clear the cost for non-referrals. But maybe this is a clarifying question for the interviewee to ask.