Power Use Overestimated in Diagnostics Panel in Network Separated with Transformer

With no change in the uptime or number of power consumers, a heavy-watt power network connected to a low watt power network via a transformer will report higher power use in the diagnostic panel than a single wire network with no transformer. (The tool tip however reports the same consumption before and after the switch)

In a save of about 700+ cycles, I switched from using a single network of low watt wires to one high watt wire network connected to one low watt wire network via a transformer. All power consumers prior to and after the switch remained the same.

Before making the switch, the Power Use element in the diagnostics panel would report anywhere between 600W-1kW. After the switch, with no increase in power consumers, the element now reports 1kW-1.5kW

I would have believed that my power consumption had increased per the panel, but upon hovering over the high watt wire, I would see the more familiar numbers I associated with my previous, single, low watt network.

Pre-switch:

Post-switch: