If you have an approach that:
Why mess with it? I’d ride this approach until either #1 or #2 stops being true. The only slight tweak would be to be a bit more conscious of nutrition during the refeed. You’re probably burning through some nutritional reserves with the repeated fasting.
If you’re looking for something subtle such as sustained 60 hour fasts doing being less efficient long-term in a way that switching to 40 hours won’t be, I don’t think our storehouse of knowledge about fasting is large enough to answer that.