yes that is one good point.
Bluffmaster said:This is my best guess :
Ben needed Locke to convince the Oceanic five to return to the island. But as soon as Locke told ben about Jin being alive and the ring, Ben knew that he could convince Sun and manipulate the Oceanic Five to return to the island. Locke was not needed anymore. Also maybe Locke working with widmore might have affected Ben's decision.
There's a chance the writers are just really setting us up for a huge surprise when we find out Ben is a "good guy" in the end - but if they are, they're doing one hell of a job. Once again,this week's episode made Widmore seems like the good guy, Ben seems like the bad guy - BIG TIME. We can now confirm that he has pretty much lied about everything off the Island (intentionally lying to Sun about Jin being alive, MURDERING John Locke, killing Abaddon, etc.)