Opposite reaction, tbh. This should've been part of his initial claim. I don't get the point of trickling details over time.
A proper town claim is direct, upfront, gives all details anyone could reasonably ask for and leave no room for guesswork or vagueries. El Topo didn't even give a reason for leaving out roy's supposed target. Not that I want it to be revealed at this juncture but...
When you're town, and you have a role, you internalize that role and reflexively keep track of everything about it. If questioned, you can bring it up instantly. By giving up details only under duress, or when you make a mistake in terminology, the impression is one of improvisation.
Basically, it doesn't feel natural.