MrSealyp on YouTube did some tests of these. Similar to those worksheets of testing you posted he noted mulching didn’t seem to give the bonus it says it does. But he extensively tested different plowing/cultivation types and how rocks present as well as rock removal / rolling, etc. As someone that didn’t understand when to do what, it helped a bit, I think.
Mulch = only right after harvesting.
Plowing / cultivating after harvesting.
Rolling only reduces small rocks (shallow cultivation.) but gives a bonus prior to seeding if I recall correctly. After plow/cultivate.
Rock pickers remove all rocks (big and small), again, before seeding.
Lime before seeding, even though it will let you do it after. I don’t remember if you get the bonus both ways.
Fertilizer during or after seeding.
Again, those were notes I scribbled because I thought I’d finally found out things I didn’t understand.
But the game presents me with plows, cultivators, disc harrows, power harrows, subsoilers and spaders.
It would be nice to know when I would want to use each one of those.