You probably have seen "Predator X" on History Channel right? I say Pliosaurs are extremely powerful predators, and this one is amazingly huge. However, I seriously doubt about their method of measuring bite force.
From what I have seen on the internet (I don't have history channel at home, so I rely on the web for my movies), they claim that by using a crocodile (or was it an alligator), which can weigh as much as 3, full grown, 500 pound lion,(or if it is an alligator, 500 pounds) and tested that its bite is around 2500 pounds, a little less powerful than an alligator, but beats any bear and hyena. Now from that estimate if a 1500-2000 pound crocodile can do that much, then a 45 ton animal 33,000 pounds.
Now I find that method of estimation filled with holes. The biggest hole is using size. Now just because the animal is significantly bigger, does not mean the bite force trend goes along with its weight. For example, it might work with animals like deinosuchus, an animal that is identical the American alligator, or Megalodon, an animal that is nearly identical to a great white shark. But you are talking about a pliosaur, something far different from any gator, or croc. There jaws have a very low profile, and are quite narrow, I don't think the jaw muscles would be all that big.
These pictures might give you a better understanding of what I mean about Pliosaur jaws
[link][link]I feel that they should only focus on jaw and neck muscles only, plus the animal's jaw structure, because comparing weights of different animals is irrelevant when it comes to estimating bite force, and that was how we got Tyrannosaurus's and Dunkleosteus's bite forces, since both animals are very different from today's birds and fishes, and we cannot rely on their modern relatives to help much.
This is just my opinion, what do you think?