Gstr 3b late fee calculatiom confusion

i alrdy read in all website.. late fee 50 Rs per day for normal return 20 Rs per day for nil return but what is confuse is.. when there are many 6 months pending.. i file febrauray as nil return but in system is auto selecting option NO for Do you want to file nil return means does LATE FEE LIABILITY cancel Nil return so what will be the auto system calculated late fee foe next month april.. is it 20 Rs per day or 50 Rs per day (i have not made any sales.. not enetered anyting in outward supplies form is 0 )