Dear TaxMan - yor answer was of utmost help. It fully answered my question and no further explanation is needed. Thank you a lot for your kindness and time.
Dear "An anwer..." - fair point and sorry for not including any details.
a) The grading scale in my country is: excellent (approx. 5% students get this mark), very good (10%), good (25%), fair (30%) and fail (20%).
b) The grades are not compared across universities so it can be that average person from tier3 Uni has better marks than very good person from tier1 uni. Hence, school's reputation plays a role and employers first scan CVs by name and only then by grades.
c) My uni is leading tier1 here so I guess quality of students is very good.
What is this "class range" you mentioned. How to read this figure?