Hank wanting to cure himself and causing his mutation to evolve was taken straight from the comics. Hank isn't a super genius, he's just a really good scientist who happened to make a mistake with his calculations.
I didn't know that was from the comics. Still, it takes more than a calculation mistake to create something that will enhance a gene when you thought it was supposed to suppress the gene.
Cells basically are like factories where DNA is the template to build proteins that serve a function. To suppress a gene, he'd have to find a way to eliminate the proteins that make him look the way he does.
So to use the factory analogy, it would be like someone designed a bin to hold and store widgets as they come off the assembly line but it instead causes the assembly line to run faster. Not entirely impossible, but improbable. Especially since you would think Hank would test it before actually shooting himself up.
Either way, I would have liked to see Beast in his natural form for at least this film. Just my personal opinion.