At around 5/5.5 months DS was waking for a NF once in the MOTN, usually around 1:30 or so. We introduced a DF around then to change the NF to earlier before I go to sleep instead of in MOTN. The first week he still woke at his usual time, and if I resettled he would wake up 2-3 hours later also. Or he would wake up later one night from his usual time, but then slowly that wake up time kept creeping back to his normal 1:30 NW. I don't remember if I ended up feeding at some of those waking or not (likely just at the later ones, but not at the 1:30 ones), but after a few more days he did start sleeping through. I would give it 2 weeks before deciding that the DF isn't working. It takes about that long to change a night habit. I would also try to resettle in MOTN, but if you think you're going to give in, I wouldn't drag it on for too long. If you think you don't have to feed back to sleep, then I would try to persevere.
DD was still taking 2 NF at this age (till 7.5 months when we weaned one of them).
Sometimes a growth spurt causes a previously STTN baby to start waking more often, so I would feed if you think she is hungry.