Payment of income tax after receiving 143(1)(a)

I received 143(1)(a) and I fully agree with the differences indicated by Income Tax Dept.

The difference was due to the bank updating the 26AS after I submitted the return.

After revising the return, I found out that I have tax amount payable by me.

My question is - whether this payment of tax comes under Self Assessment tax (300)  OR  Regular Assessment (400)?

Please clarify.

Thanks in Advance.

Mallik