Cappy – unit entitlements cannot be used to detetmine a quorum, but the SCMA does mandate Special Resolutions (and votes by unit entitlement) in specific circumstances including for voting on changes and additions to the Common Property of the Plan, creating Special By-Laws, and for revoking exclusive use privelages. Incidentally, it also mandates a unanimous vote on any motion to wind-up the Plan.
In terms of the Agenda for General Meetings, Special Resolutions must be called for (and be “flagged”) where mandated under the Act (refer above), and Ordinary Resolutions (simple majority / one vote, one value) otherwise, so your Strata Manager is acting appropriately if they’re preparing Agendas in that way.
However there is one useful provision of the Act that’s particularly relevant in circumstances such as exists in your Plan with its spread of unit entitlements, and that’s a “poll vote” where a majority of votes by lot unit entitlement determines the outcome (ie 51% determines the outcome).
In that situation, it is where permitted usual for a vote on an Item to be taken by an Ordinary Resolution (i.e. one vote / one value) and if the outcome is considered for any reason to be inappropriate by any one Owner, then that Owner can call for a “poll vote” on that same Item where the votes by those Owners whose Lots have the highest units of entitlement hold sway.