Are we on the same wave length here??
Usually a 3-5 means that service and supplies are provided for three years, after three years the customer then has to pay for service, thus raising the cost to them. ie: $100 per month for 60 months includes 3 years of supplies and service for 100K, after the third year or whenever the supplies and service expire, the rep will come back in and refi the remaining 24 months with a new 3-5, they can usually sell this at a lower price that what the customer would have had to pay for adding service. The rep gets the new deal and signs the customer up for another 60 months at lets say $200 per month, and then this happens again in three years.
If this is the cse this is a sure fire way to never ever get a third upgrade out of the customer and puts you at risk for losing the account forever.