dividend tax

I am doing audit of a govt listed co. It has proposed a dividend and created the provision for dividend tax on 31 March 2010  @ 16.995%(15+10%+3%), but the dividend was declared in AGM on 21 Sep2010. At that time the rate of dividend was 15%+7.5%+3%, so co.paid the tax @  15%+7.5%+3% on 4 oct2010 and the ba;ance provision is appearing on the liabilities side. Should the co. reverse the provision on 21 Sep 2010, the date of AGM or on 4Oct the date of payment. I have to finalise the accounts from 1 apr to 30 sep.