I agree with Laura, the DF does not work for every lo, and in turn can sometimes end up causing more nightwakings than previously as it can disturb their sleep.
The book does suggest dropping the Cluster Feed at 6 weeks, however some mums prefer to stick with the cluster feeding as it works well for their lo.
That being said, I would definitely give the DF a try for at least a week to see if your lo takes to the DF. Definitely try offering the DF closer to 10pm and see how you get on.
Good luck, and keep us posted on how you get on.