Epic issues.

[Tvtyrant]

The Epic Pseudonatural Creature template gives a CR of +10 to a creature with 16 HD or more. Applying the template to the Cloud Giant makes a CR 21 monster (same as a Titan) that has the same bonus and DR, considerably more AC, twice the movement rate, more health, 4 extra attacks (if you use the Maul and tentacles rather then just tentacles), a strength of 57 (compared to 43), SR 80 (to Titans 32), and is essentially all around a stronger creature.

Is the calculation method for epic really so broken that those are the same CR?

[Ryuuk]

In the Titan's defense, it has Gate, Summon Nature's Ally IX, Meteor Swarm, Maze, Etherealness and Word of Chaos as spell like abilities as well. If those are used wisely, it might be able to beat the Giant, and quite possibly present a greater challenge to a party.

With regards to CR and Epic though, it's probably best not to bother with it.

[Thrice Dead Cat]

To be fair, most CRs are wrong. You use them as a baseline and wing it for EVERYTHING.

[The Tygre]

Yes, but to be fair, Wizards did rectify the Pseudonatural template in at least three books. Though I sense that's not really the issue. Do as TDC said; CR at those levels is, at best, a baseline.

[hamishspence]

Strictly, the Epic Pseudonatural template, and the Pseudonatural template, are separate- since the Epic Pseudonatural template was updated to 3.5 in the free online update, and is on the SRD. Whereas the Pseudonatural template is in several other books- which weren't included in the SRD.

I think the "ordinary" template first appeared in Tome & Blood- was that very shortly after the Epic Handbook came out?