Hi Rizzo,
If you've given it a full week of trying and not noticed a difference, then I would say you probably don't need to be doing it. The DF doesn't seem to work for all babies and in fact can be disturbing for some of them as well. Some moms also choose not to DF, so they can go to bed earlier. It really is kind of a personal choice. You may try for one more week, if you're not keen on dropping it, just to see if he stretches out at all. Whatever you think works best for you.
In your case, since the days are not quite ironed out yet, it's hard to tell what exactly might be disrupting your nights. It is very common, however at 3-4 mo for a bit of regression in NFing. One, because of growth spurts and two because of LOs 'awakening' more and becoming a bit more distracted at their daytime feeds. I think your best bet is to try to get your day ironed out first, continue to make sure DS is taking good, full feeds, and feeding him in the night at no shorter interval than 3-4 hrs (whatever you feel appropriate and most comfortable with). Hopefully as you work on those things and the developmental stuff goes away, the NFs will go back and stretch out on their own.