If it works carry on, especially if you aren't doing a dreamfeed.
I *think* it's to do with getting a good 3 hour EASY all day really and so as not to encourage snacking but to get a good feed at bedtime. If it works for you it's fine though, a lot of people will do a pre-bath bottle and then a top up after the bath which is a type of cluster.
Sounds like they are doing well!
Laura