Thanks for moving this topic! WAK;
As John has mentioned, contact the Utility Company and verify the request with a Service Planner.
Seems to me the POCO is requesting Load Calculations for this Existing Service, so as to verify the Existing Service Feeders (and maybe the Transformer too) will handle the peak Calculated Loads.
They (POCO) may think there has been some Remodeling done on the Property, which could affect the Peak Load; which is likely to occur in One Years' time.
An accurately compiled Load Calculation Database will include the Calculated Loads for both Tenants and the "House Panel".
NEC Article 220 contains the information.
Basically, the Loads will include:
a: 3 VA / Square Foot - General Lighting,
b: 1500 VA per Small Appliance Circuit,
c: Electric Cooking Appliances,
e: Electric Water Heating,
f: Laundry Equipment,
g: Electric Motors.
Wish there was more to include, but I rarely perform Residential Load Calculations!