Interest for late filing and payment of tax under GSTR3B

suppose if a company files gstr 3b for the months of july 18, august 18, sept 18 on 25 jan 2019.here my question is whether they will attract any interest for that 3 months?

(note: due date extentend for the above 3 months was 31.03.19)

explain the answer considering the note point and if any notification from cbec regarding the above question please furnish