Kind of like where employers call employees "contractors" because they can get away with it. It looks like the purpose of a deed is to announce intention to uphold a promise such as debt repayment in exchange for title.
The idea of a deed of assignment (from googling) is that one party transfers ownership of an object to another party. If OP's earlier contract was valid then this would be extraneous, if OP's earlier contract was flawed then it would be in his/her best interest to negotiate a new contract as a deed would basically be giving away the vested interest they have.
Anyone that makes a moral argument here needs to remember that using the legal tools available to you is not immoral. It may be mean, but it's fair play. Bill Gates and Spyglass, as atrocious as it was, demonstrated this. If the original contract was flawed, then OP actually owns some vested component of the company/product.
Why in the world would OP give away something that has literally just been assigned a value for free? Frequently companies, if in the situation of OP, will leverage their legal rights in this scenario.
I still think OP should negotiate some compensation for anything they sign.