There are really two questions here. What you have done is fine in terms of the standrad. The answer to the second one is more difficult. Often times registrars have a paradigm about what one must do in order to meet certain requirements. In these cases you must either conform o convince the registrar that your method is also acceptable.
Most people choose conformity.
If you want to convince the registrar, then you should do it before the audit. Remember, they are your customer, and you are paying a lot of money to have this done to you.