Systems and methods of insuring payment of a proper amount of postage, comprise receiving payment for an amount of postage, affixing a postage indicia to a piece of mail, wherein the postage indicia includes the postage amount in a format readable only by machine, and adjusting the postage amount at a time subsequent to receipt of payment. If the vibration waveform includes a waveform of vibration of noise components, the correlation coefficient K is calculated to be smaller comparing with a case of not including it. Dependence upon similarity of place names is eliminated. The controlling unit controls the image-forming unit to perform the image-forming operation in the mode determined by the determining unit.