sel4 cost of loc

Answer
According to the search results, the cost of producing formally verified, high-assurance systems using seL4 is on the order of $200-400/LoC (Lines of Code) for critical code. However, the total cost for development of seL4 and its functional correctness proof is $362/LOC, which is low cost compared to the industry rule-of-thumb cost. Additionally, the cost of the proof for seL4 is higher, in total about 20 person years, which includes significant research and about 9 person years invested in formal language frameworks, proof tools. It is important to note that building a system on seL4 requires more work compared to building on other operating systems like Linux.
Related
What is the cost of producing formally verified, high-assurance systems?
How does the cost of producing seL4 compare to other microkernels?
What is the cost of developing seL4 and its functional correctness proof?