Most customers choose to lease the equipment, and with this type of close you need to take the amount of discount and divide by the term of the lease. ie: $1,000 divided by 60 months equals $16.66 per month, from there deduct this amount off of the monthly price that was quoted. Do not take this off of the purchase price. You have agreed to save the customer one thousand dollars and you have done so.
Here's another example. Price for the system is $20,000 with a rate factor of .0195, thus the payments are $373.34. When you minus off the $8.33, the new lease cost is $381.67 and will create a new sale price of $19,145.64. If you had taken a thousand dollars off of the $20,000 you would have lost the $145.64 on the transaction.
Remember that when selling payments, you are saving them a $1,000 over the term of the lease. You also have to be specific in how you state it, once you say that you are selling the system for a $1,000 less then you must go with that, however if you use the close that you will save then "x" amount of dollars if they buy today then you can use the formula I outlined above.