By having a factoring company finance your invoices, your company is effectively leveraging their ability to borrow capital when you cannot. Borrowing from a lender comes either in long term qualities or short term realities. Once a business qualifies for a loan from a bank, for the most part a computer somewhere takes over the servicing of the loan. Meaning, the technology makes sure your monthly payments are made on time according to the terms fed into the program. The reason this works is the bank has determined there is stability in the operations and profitability so they can afford to take on the long term risk when making the loan. This is why the current commercial finance situation is so tenuous. Many businesses are having a tough time showing they have historical stability.
Factoring on the other hand is considered short term capital, meaning there is a very short leash for the borrower to get into trouble. By financing 30 day net term invoices, if trouble comes along someone will know about it within a couple months, which incidentally makes it easier to rectify. Because most factoring companies have much more leeway to work with their borrowing clients, things like unpaid invoices can be worked out through advances and reserves.