With refusals it's often the case the more than one reason will be mentioned. In your case no other application weakness has been mentioned by the ECO.
It's not normally the case that a different reason for refusal is pulled from the hat. If finances were marginal I would have expected the ECO to have cited that if he had sufficient doubts.
From all you've said it looks to be related only to the application and missing/incorrect information.
To be honest, I'm still surprised that following the telephone discussion, the ECO took the decision to refuse.