It's not as egregious an error, but Hank should know the confession wouldn't stand up. The story about Hank selling Walt to Fring is absurd on its face, no one sells a golden goose. The murder of Boetticher is impossible to fit into the scenario. The unforgettable spectacle of a giant magnet toppling a truck against the wall of an evidence room to destroy computer evidence shows the confession is nonsense as well. Either Hank would have destroyed the evidence himself (presumably lest Fring be taken alive) or he would have gone ahead and used it.
The DEA itself knew that Hank wasn't druglording it when he was detailed with the agents going after Tuco. Nor was he when the DEA had him under close guard for a prolonged period of time. In general, Hank's pursuit of "Heisenberg" when it even jeopardized his career is completely irreconcilable with "Heisenberg" being under his thumb the whole time. Hank's career is gone when it all comes out, but Hank knows that already.
Sorry, but the writers are losing the plot.
I agree there are some definite holes in Walt's story, but again, I think his main purpose was just to make things as difficult as possible for Hank with the DEA, and make him have to jump through so many hoops he might decide it's not worth the trouble.
Of course it could also be argued that Hank's entire investigation (and everything else he supposedly did) was simply a smokescreen to cast suspicion away from himself and Walter.
And who knows. Walt's a good enough liar that he could probably come up with an explanation for all those other
issues as well, given enough time.