A manufacturer server 110 that determines a first invoice amount or calculates a second invoice amount for an inkjet printer has a billing status acquisition unit 342 that acquires billing status information including actual print volume PV. In a preferred embodiment, the auto-latch mechanism includes opposing guide plates and a plunger pin with a distal portion movable to a location between the plates. A second group of concavities may be formed in an upper face of the impeller. Delay elements may be provided in antenna output channels, or with suitable code construction delay may be omitted. The processor can also display a unified icon shaped per the rate of change, with a prevailing color determined using the values. The length dimension can be greater than the width dimension and the height dimension can be greater than at least half a height dimension of the slide device and the action figure collectively.