I think its well worth trying. The DWP do a reassesment as a matter of course anyway, as soon as they receive the "if you think our decision is wrong " form. With all their information in it, It may be classed as new evidence.
I would also call them and tell them, that you disagree and will be sending new evidence. Make a note of who you speak to, time and date, what is said. If you can, keep copies of everything you send them.
Personally I think the new small form is scandalous. It gave me the wrong impression altogether.