I tried looking for you to find the answer, but Bose doesn't have a recent credit card agreement online. The only one I could find is from 4 years ago
. If the terms are more or less the same now, then yes you are correct - it's only no interest if paid in full. If you don't pay before the time is up, then you get hit with the back interest.
They do have a 0% payment plan that you can use your own credit card for. Here's how it works
Now: 0% interest from Bose
Choose the BoseÂ® payment plan and make low monthly payments using your own credit card—with 0% APR and no interest charges from Bose. Just tell us which card you wish to use and select the 6- or 12-month payment option.
The Bose payment plan is available on orders of $299 – $1500* paid by major credit card. The 6-month option (web-based orders only) includes an initial down payment of 1/6 the product price plus tax and shipping charges, charged when your order is shipped. Then your credit card will be billed for five (5) equal, monthly installments beginning approximately one month from the date your order is shipped.
The 12-month option includes an initial down payment of 1/12 the product price plus tax and shipping charges, charged when your order is shipped. Then your credit card will be billed for eleven (11) equal, monthly installments beginning approximately one month from the date your order is shipped.
Your best bet would be to do that with a non-Bose credit card that offers 0%.
Here is our list of the longest 0% credit cards
(sponsored). If you're currently on the deferred interest plan, you may want to get one of these to transfer the balance to, if you can't pay it off in time before their retroactive interest kicks in. Good luck!