Are they really tired at bath/dinner/evening time? I think your kids and my own share a similar HIGH voltage setting, and whilst its not always desirable, an extra movement activity might be the go-er? I've found nature walks on a windy arvo, or just this week FMS focused activities on the oval, a lifesaver in terms of really wearing them out, before quiet time (dinner/bath/book) begins. It's also become a great incentive for DD for the next day