I design tariffs, power-saving rewards and an app for Japanese households who should be able to explain their own energy bill without calling us.
The first complaint I answered properly came from a retired schoolteacher in Matsumoto in 1998. Her cable television bill had risen by ¥840, and she had read the enclosed notice twice without finding the reason. The reason was there, in the fourth paragraph, behind a phrase about revised channel packages. I was a billing analyst at Shiokuma Cable Television, a year out of Minakaze University with a degree in economics, and my job was to confirm that invoices matched contracts. Her letter taught me that a correct invoice can still fail the person who receives it.
A household should be able to state the rule of its tariff from memory and predict, roughly, what next month will cost. When that fails, the customer is not careless; the product is unfinished. I would rather sell a simpler product to people who understand it than a cleverer one that only our engineers can follow.