Do not worry if you can not exactly match a paper feed unit with your calculation but use this as a guide to what you do require. If the calculation in 3 above exceeds 5000 sheets then you are doing some serious copying and will undoubtedly want an operator to be on hand to recharge the LCT regularly. Most copiers are limited in their A4 capacity to about 5000 sheets. They are generally confined to the domain of the analogue copier and are being replaced as an output device on digital copiers by modern finishing units. If stapling was required, this had to be done downstream of the sorter after all pages had been collated.
Finishers have a lot less limitations and therefore inherently deliver greater productivity.
A finisher collates output copies by offset stacking the sets. If the sets are to be stapled then the finisher does this as each set exits the finisher and eliminates the need for separating sets by offsetting. Some finishers also offer the option of multiple output bins. These are not to be confused with the bins of a traditional sorter that separate sets but are used to separate jobs that may have been printed across a network from different users. Network software usually permits selection if the output bin, if multiple bins are available.