Numbers are only a suggestion. Just carefully keep the angles as consistent a possible. Raise a burr on one side, sharpen other side and hope that both edges meet without creating a pronounced wire edge. It's nearly impossible to eliminate burr in it's entirety but if you do a good job keeping consistency the edge will be good.
Just because you can sharpen at steeper angle doesn't necessarily mean it's better. Suppose you happen to sharpen at a less steep angle but do a very good at keeping the angles consistent. I don't think you are going to complain about the performance