Excuse me, how to calculate the electricity loss fee in Longgang, Shenzhen, is it reasonable?

The "line loss" charged to you (professionally called line loss) is reasonable in terms of power supply principle. Because there is a transformer and a section of line between the power supply company and the landlord's metering device, it will consume electricity. But whether the specific 5% is reasonable depends on the actual situation on the spot.

Even if it is reasonable, since there should be a contract with the landlord, it should be in accordance with the contract. You can also re-sign the electricity contract, and calculate the real loss based on facts and friendly negotiation. How much is this loss? According to the difference between the two-stage watt-hour meters, it should be well calculated.