40 Hrs for 1 scenario, and as you point out that is just the actual working time, plus concept development (Thinking) can add a lot more, then multiply by 4 to 11 scenarios in a campaign… that would blow up from 40 to 200-400 hrs plus.
That is a lot of work that I am grateful for it, Thank you.
As I mentioned in another conversation (Outdated custom campaigns are no longer playable - #7 by Louis0108) you and all the creators of Campaign and Mods should get some reward, as a creator, please give us your input on the subject.