Why would you use the percentage of sales method of calculating doubtful accounts as opposed to the percentage of receivables method?

I am sorry. But no one in the world knows the answer to that question. We have gone to every state and country but no one knows why. Heck, we dont even understand the question! Percentage of sales is based on the company history, or perhaps the industry standard for losses. If business has been steady than it is simple to predict based on past history what the uncollectible accounts will be. If there is no past history to judge by or industry standard, than percentage of account receivables takes a percentage of the actual amounts due at the end of the period. Since Sarbanes-Oxley Act of 2002, it is very important to have a reliable method of judging receivables, often the biggest liquid asset of any accrual based company. (all public companies). You need to know how much receivables will actually be received to properly value the company. I