Keep the feeds you are doing, clusters are usually at 6 and 8 so a feed at 4 and then 6.30/7 isn't a cluster it's a normal feed pattern. If you were doing a feed at 4pm, then 6pm, then 8pm you would combine the 6pm and 8pm feed into a 7pm feed so it would be 3 hours from the 4pm to 7pm bedtime feed.
HTH!
Laura