In the 10-page proposed change, my sense is that the key points were in this quoted text:
“To reduce the cost of implementation, this proposal avoids the need to replace meters by using SCADA to profile the demand across the thirty minute trading interval, where 5-minute interval meters are not installed. This enables generation payments to be made on a volume weighted basis, rather than a simple average dispatch price over the trading interval. Participants may choose to install 5-minute interval meters at their own cost.
In recognition of the fact that not all loads are capable or willing to undertake rapid demand-side response, and not all loads have suitable metering or SCADA, the proposal provides for optional participation in five minute settlements for loads, which should also help to reduce implementation costs”
… with our emphasis added.
The Sun Metals application referred back to the NEMMCO process, which concluded with this final report in February 2003.