If he's your only one on that routine, I'd just go to a 7-day schedule. One day isn't going to make that big of a difference, and it might be simpler to just have every Wednesday as feeding day (for example).
Yes, you can even feed your snake every 4 days, but you only do that to get your snake to get some extra weight.
If you have a healthy adult or sub adult, or even juvy and you're feeding 10-15% every 4 days you are very likely power feeding. There's no good reason to feed a healthy bodied 1000gram snake every 4 days In the end you will do more damage than good. Even my females that lay and come out of the breeding season 600-700 grams under their pre-season weight don't get fed every 4 days.