"Bishop Don Magic Juan" insertnamehere.co.uk wrote

...Must wait at least seven days for Roundup to do
its work. Tilling a few hours after application competely nullifies the
purpose of Roundup.

No. If that were the case then Roundup would be rendered ineffective if it
rained or there was a heavy dew any time within a week after application.

Any type of herbicide (selective or universal) requires a few hours to soak
in. It then takes a week for the plant to die. This will happen whether the
soil is turned over or not (except of course that turning the soil over
increases the damage).

Read the instructions on the bottles. It explains it all.