Step-by-step, Step 1. Identify candidate systems for submetering (E)
Modify the second sentence to read: "These subsystems may include residential units, irrigation, indoor plumbing fixtures, domestic hot water, process water, reclaimed water, and cooling towers."

Further explanation
Below the Calculations section, add a Rating System Variations section that reads:
"Rating System Variations
Multifamily
When metering 50% of residential units, also meter one other subsystem for 1 point. When metering 100% of residential units, also meter two other subsystems for 2 points.
If metering indoor plumbing fixtures and fittings, domestic hot water, reclaimed water, or process water within individual residential units, it must be done uniformly (in 100% of units). Projects still need to meter full subsystems (for common areas or the whole building/project) to earn credit."

Delete the Multifamily section in Project Type Variations.