What does his ability amount to? Is this inferring one could spend the target lock and then get it right back
The timing "after" means immediately after the trigger, before moving on to another step. So, right after rolling dice, before moving on to the dice modification steps (where you could spend locks etc), you can acquire a target lock. Then you move on to dice modification and can spend the lock if you like, along with a focus token etc.
Note that it happens too late for a missile or other weapon that requires a lock, so if you don't have a lock already, you'll have to declare a different weapon (just your primary weapon).
The gist: This means Vessery could Focus as his action, and get a free lock if someone else locks the target for him, giving him very strong dice modification. Add Juke or Outmaneuver just to be evil. As long as an ally is supporting him with locks, Vessery's attacks are hammers and the enemy faces high average hits/crits with most attacks he makes.
BTW as a note on the wiki itself: you can go to Colonel Vessery's page and post in the comments section there to get faster help. I only check the forums every once in a while, and the wiki doesn't inform me of new posts or list them in the wiki activity like it does almost everything else. Fandom's new "discuss" forum is kind of a mess, and a lot of its features seem like afterthoughts or never-thoughts. ;)
What do you think?