Time of Supply

As per the provision of sec 13(5) of CGST Act, "Where it is not possible to determine the time of supply under the provisions of sub-section [2] or sub-section [3] or sub-section [4], the time of supply shall--

[a] in a case where a periodical return has to be filed, be the date on which such return is to be filed".
With reference to this clause, I would like to know if time of supply be the date on which such return is to be filed, then tax liability should pay in next month upto due date of GSTR3B of the same month. Am I right?
Kindly let me know.