Schedule 234A - penalty despite tax paid?

This year, last date to file ITR was extended till December 2020

I had a self assessment tax to be paid = 2 Lakh.

I paid that in September and hence, apart from that, I had to pay 4000 for the 234A for the 1% per month interest for 2 months post July 31st

I thought I am done with taxes and today when I am about to file ITR form, they have increased by tax liability by imposing penalty of 6000 more in 234A for the 3 more months (oct-nov-dec) despite payment made.

Is that problem with utility or that is how tax is levied?

This is cheating by government.