Can I extend my 30-day visa on the 6th instead of the 9th to avoid two trips to immigration?

Hi there. My 30 day visa is due for 30 day extension on 10th this month which means a trip to immigration on the 9th. I need to head down there to do my children’s report by 6th(last day 7 days after given date) Is it possible I do my extension on 6th to avoid 2 trips? I am planning to transfer to guardian visa so not worried about losing a few days. Thanks.