Appraisal

I am buying a condo(mid-300's) and it appraised for 30K less than I am paying for it(which ends up costing me more money at closing). I looked up the #1 comp listed in the appraisal report, and it turns out it was an "all cash buyers only" listing. The #2 comp in the report was listed as renovated, but streeteasy shows the original listing being sold "as is." I called the appraisal company for clarification, and the person argued that these were good comps regardless. Is it just me...? He was especially adamant that all-cash-only listings do NOT have depressed prices..is that true??