Has anyone had their Toyota "bought-back" early? I have a question about the 65 000 km thing

Hey all,
We are 4 years into a 5 year lease for our Sienna (in Ontario). Our dealership contacted us and is essentially paying us 12 000$ to get us to resign on a new lease early and repossess our van (since they can still make a profit!).

Twice, they asked how many km we had on our car. Both times we told them, they said OK great so under 65 000km.

My question is this - we are getting ready to sign for a new lease, and will then await for the vehicle to arrive which will likely take a few months. But, I used my car for work AND am planning a trip that would add around 1300km to the car. My question is, what happens if we go over that 65 000km? Do we suddenly lose out on the 12 0000$ because the car isn't as valuable once you're passed that point? Should we let the dealership know ahead of time to try and get a vehicle sooner rather than later?

I'd love advice from anyone who has been there.