I'm not getting same experience. Cleared a bench waited 5 days. On a settlement with 10 stations. And nothing appeared

Well that looks like being a glitch.

Not dissimilar, perhaps, to some funny goings on with my game at the moment.

After the last patch i am finding water not appearing in some workbenches but some other benches are showing an excess of what should be there.

I also have bunch of Scavenging Stations across the map. Some settlement may have 2 and up to 5.

But I'm still not impressed with the result.

I only ever built one scrapping station.. I don't think I ever assigned it. . Wood and steel are everywhere.. You scrap the entire settlement of Sanctuary and you've got enough to build 3 settlements. The only junk I ever ran out of in the beginning of the game were screws and adhesive.... And that was basically only because I impatiently wanted to mod every gun and armor piece I came across. After awhile of ignoring any sort of modding I didn't even need to worry about those items.