There are differences in the calculations. A loan has a fixed amount, and payment is made at certain times. The terms of repayment in factoring depend directly on the debtor, and the contract does not have an expiration date, unlike a loan. Factoring is done regardless of the borrower's goals, while a loan requires goals. Take a look at the specifics at https://factorforyou.com/california-factoring/ and you'll understand why your calculations may not be accurate enough. Depending on the type of factoring and the terms of the factor, the fee is paid at the time the financing is issued or after the factor receives 100% payment from the buyer.