For the VCAA, the percentage attendance is irrelevant - the VCAA states that you must have 50 hours of face-to-face teaching time for the unit.
However, this is not the minimum attendance for your school. Each school is entitled to set the minimum attendance rate for students, and this will be upheld by the VCAA as long as it is above 50 hours.
References:
http://www.vcaa.vic.edu.au/schooladmin/handbook/2011/AdminHand2011-PartC.pdf- "The N result should be used for students who only partly complete work or whose attendance records breach school
rules."
http://www.vcaa.vic.edu.au/vcaa/schooladmin/handbook/2009/partB09.pdf- "All VCE units require 50 hours of class time. A student needs to attend suffi cient class time to complete work. The school
sets minimum class time and attendance rules. Where a student has completed work but there has been a substantive
breach of attendance rules and the school therefore wishes to assign N to the unit, the school must assign N for one or
more outcomes and thus the unit."
The key here is that legally AND ethically, the school
must assign you an N for the unit if you have substantially breached school rules in regards to attendance.
I'll be honest - if I were you I'd make sure not to miss a single class for the rest of the Unit, or be prepared to accept an N. You've already reached what I would consider a "substantial" amount of missed classes beyond the 10% accepted by your school, so you're working on their good will at the moment. Unless you have recourse to file for Special Provision, don't miss any more classes!
Hope that helps (and hope it doesn't offend, just making sure you know where you stand).
-MC