Paying scrutiny demand while filing CIT(A) appeal: Should I select Minor Head 300 or 400?

I received a scrutiny assessment order and am filing a CIT(A) appeal. To stop interest under Section 220(2) from accumulating, I am paying the demand amount.

I need advice on which Minor Head to choose on the e-filing portal:

• My CA’s perspective: They say I should pay under Minor Head 300 (Self-Assessment) because we are paying "under protest" and do not accept the order, so we shouldn't select 400. He is saying 400 would mean we have accepted the order.
• My confusion: Shouldn't this be paid under Minor Head 400 (Regular Assessment Tax) since it is being paid against a Section 156 demand notice?

Does selecting 400 mean legally accepting the order, or will selecting 300 cause issues with the portal not clearing the outstanding demand? Which Minor Head should I actually select?