Ross,
You haven't a case.
Your procedure states that 'you conduct internal audits quarterly'. That's a schedule, and a perfectly good one. But you spoil it by saying you publish schedules in "a timely manor". This indicates that the real schedule is yet to come and here, in March 2000, it hasn't come yet. It's a bit late for publishing information about what is happening in Jan-March, so it's not 'timely'.
Keep it simple, explain why it works for you and, although you can leave it as flexible as you like, be specific as to what flexibility you are allowing and why - don't leave it loose so that the auditors find their reasonable expectations are not being met.
If I was the auditor I'd say that your actions were not complying with your planned arrangements and ding you against 4.17, internal quality audit and 4.2.2 b, not effectively implementing the quality system.
rgds, John C