The rate should be near 1.3 / KWh for HK Island, and 1.1 / KWh in Kowloon. As pointed out above, while it is illegal it is very common for sub-divided flats. You can complain and then the utility will cut the power so all three units have no electricity. Many have complained that sub-divided tenants will not benefit from the new electricity subsidy from the government, the meter owner will get the benefit.