If your company is registered in FY 12-13 then you should appoint auditor within one month of company incorporation and after appointment of first auditor you intimate Form-23B as first auditor for the FY ending 2013. without additional fee.
For old Financial year you will file Form-23B with fee along with 10 time of additional fee.
29 December 2012
With due regard to both the experts I beg to differ that for every appointment you have to file Form-23B. As per Sec 224(1A),Form-23B needs to filed only for the Auditor who is appointed in an AGM only.