To me that is only a guide line.In my opinion, you should concentrate on the assignment at the best rather than worried about the date. do your best and submit.
Never think that, It is something like, you can submit version 1 now and Oracle will evaluate and say 'correct this part' then you are done.
Oracle changed the grading policy after I submit my assignment, they introduced part minimums, what can we do ?
Bottom line is complete the assignment with the mind set of want to will at the first go. If you can wrap things up by August 27th, that is great but even if you are not you are not loosing anything if you win at first go.