I'm building software account.I quite understand what he about to mention.When big company involve,the lot of passing layer from document a to document b. Actually this was very infective upon implement.Performance very weak. In real life,single ledger is more then people need.Double entry ledger for those requirement MSAB,FRS,FS whatever. Another page saying triple accounting was future transaction ? Sometimes Customer wanted simple application,sometimes customer wanted super complex flow system.Kinda hard to fulfill every their wishlist.