it'll grey out if you don't have enough, but I often caught myself adding based on efficiency instead of worker availability. So we get how many units per worker, but we don't get how many workers are added at each level. that's simple enough to start, but once you get into the high levels and non-round numbers it's easy to lose track of whether something took 2 workers or 4 workers or 5, etc. Then I'll look back over way later and realize that my allocation was stupid or wasteful and I would have had way more workers ready to dump into healers if I did it the right way.
Oh, I think I get it now. You mean like for the Tree cutting it takes two people, but after building 20 it says that it takes 40 people and you forget that it's two per building? I see.
You think if I add this info to "Cost" it will be confusing? Like, it will say Cost: 10 tools, 2 pops, but will subtract only tools