You are correct. You (and now Melbourne studios) can offer indoor classes to adults 19 years and over, providing the following conditions can be met:
The number of members of the public permitted in each indoor space and in each group, class or session at any time is limited to the lesser of: A density quotient of 8m2 per person, as per the rules for working this out 10 adults The number of members of the public permitted in the facility at any time is limited to the lesser of: A density quotient of 8m2 per person, as per the rules for working this out 20 adults You can ensure members of the public are reasonably able to maintain a distance of 1.5 metres from each other; and shared equipment is cleaned between each user; and  there is no physical contact, other than in an emergency, between a member of the public and any other person otherwise permitted to attend the facility; and only one class or session commences at a given time and that time is at least 15 minutes after any other class or session has commenced; and the facility has a COVID Marshal onsite during the operating hours of the facility; and the person complies with the records requirement and the restricted area requirement.