As a changing line this stroke warns a querent about the specific trap of an easy win. Whatever is being corrected, contested or set right has folded immediately, and the danger is no longer the opposition but the querent's own momentum. The image of biting so readily that the nose is lost describes force applied after the need for it has ended, and readings landing here often concern an argument already conceded, an apology already offered, or a concession already granted, which the querent is still pressing.
The line is unusual in granting no error to a situation it has just pictured as excessive. That grant is conditional on the centrality the stroke actually holds, correctly placed and central within the lower trigram Zhen, so a querent should read it as available rather than automatic. It is extended to someone who catches the overshoot and stops, not to someone who continues on the grounds that the text promised no fault.
Practically the counsel is to name the point at which the matter is finished, and then honour it. Compliance that comes quickly deserves to be met by a correction that ends quickly. Where the first line advised proportion before anything had moved, this line advises knowing when to stop once everything has, and a querent who cannot answer the question of what would count as enough is being shown exactly why that answer needs settling now.