15 week old twins too tired to take bedtime feed

[Twinmum256]

My baby girls are 15 weeks old, I feed same time everyday 6am, 10am,2pm,6pm and 10pm.
I'm finding they're far too tired at 6pm feed to take full feed. They go down after this feed and we feed again at 10pm but they can be but unsettled first hour or so and I really wanna make sure we get more into them to last through the night.
I've read about splitting this bedtime 6pm feed, does anyone have any experience of this? Thx