Oh I would let the designer know-after all we are human and make mistakes in our lifetime!
I need clear readable instructions as I am getting older and need to be sure of what I am doing.. I just was working on a top for one of the GD's and had to re-do it as the instructions skipped a step in the process. So I ended up ripping out and re-doing it my way instead of the pattern's way. Unfortunately the pattern is so very out of date (bought it when my kids were little), that I am sure its in the no longer made items !LOL might even be re-vamped by now category !LOL