I didn't mean to suggest that truthfulness on its own was a sufficient qualification to be a Minister for Finance or, indeed, for any other job (except, perhaps, soothsayer -- but there don't seem to be many openings for them nowadays).
It's an interesting and tricky matter to judge what technical skills a Minister needs, or even how much professional familiarity with the area. Does a Minister for Agriculture need a background in farming or agri-business? Does a Minister for Children need to be a parent (or a child)?
Some reports in the Department of Finance are quite technical, and one needs appropriate expertise to understand them. It might be economics expertise, or it might be accounting expertise, it might be legal expertise, or it might be expertise in another area. There might be nobody, even in the department's permanent and expert staff, with the full range. So the Minister must rely on the assistance of a team of experts. What I think went wrong here is that the import of the report was missed: some person or persons in the Minister's team made a big mistake.
I do believe it was a mistake, not an act of deception. I might be wrong about that.