Bun rewrite and FLT formalization had nearly identical resource usage

The Bun rewrite took 11 days and used 5.9B tokens:

https://bun.com/blog/bun-in-rust

The FLT formalization took 11 days (!) and used 6B tokens.

Why the similar numbers? Why are the numbers so low? 6B is just enough for 6 agents at 1000 tokens/s running for 11 days.