Government operates the same way. Settling an estate last year my grandmother's accountants rushed to get a massive payment in before the deadline as fee's and interest would quickly be in the 10's of thousands of dollars for filing late...makes massive payment, gets letter in the mail months later "you owe us 6 more dollars" she makes trip to the bank to pay it. Another letter comes October "you owe us hundreds of thousands of dollars" accountants notified, sent in proof it was already paid. Original filing payment was almost 50 grand over, and due a refund now after all settled and done....that was back in November, still waiting for the refund cheque.
Funny the CERB scammers could set up a fake business bank account and receive 10's of thousands of dollars unquestioned in no time, yet when it is legit they take their sweet time, make you chase them down and really work for it.