Depending on the Lease vendor, they may provide cleverly designed Lease documents, with two payments streams on the document.
The bad copier sales person fills in the agreed Payment #1 amount with the customer and leaves the Payment #2 line blank. The customer does not even see Payment #2 because it is blank.
The customner signs the lease.
Back at the office, this same sales person fills in Payment #2 with the Step Lease amount, and submits it to the Leasing company.
Working with a less than ethical Lease sales rep, the Lease company only checks that the equipment has been installed and asks nothing about the payments.
The Lease sales rep "jams" the lease through his system to get the deal funded and earn his commission.
The customer makes their first payment and the deal is done. 37 months later, they see the increased payment and bitterly complain. There is nothing they can do but vow never to buy from that company again. But people come and go in companies and the Step Lease is forgotten.
Unfortunately, many companies are embarrased to admit to another copier sales rep that they have been taken. So embarrased they sign another Step lease to escape the increased payment and put the whole issue off until another day.