英语翻译
Inotherwords,consumerreactiontoashippingfeeschedulemaybebasedonboththecurrentfee
structureandalsosomefunctionofthepastfeestructure(s).
AsasummarymeasurewedefineSHtottobethesumofthe
threeordersizefees.Thisvariableisusedtocomputeachangeinfeesvariable