What an area rate does and does not cover
A rate per square metre works when the space is genuinely uniform and the task is genuinely singular, such as machine scrubbing an open floor. Outside that narrow case it breaks down quickly. Racking reduces the accessible floor while increasing the edge work. Dock aprons collect more soil than the middle of a building. Amenities, offices and a lunch room occupy a small share of the area and a large share of the hours, and none of that appears in a single rate.
The other weakness is change. When a Botany site adds a mezzanine, converts an aisle to bulk storage or takes on a second shift, the floor area may not move at all while the workload moves considerably. A rate-based agreement has no natural way to reflect that, so the conversation becomes a renegotiation rather than an adjustment of a schedule that both sides already understand.
