So here is my view on this ,
From a purely Financial perspective the deal does not make sense given the fact that your existing bike is in really good nick with low mileage.
Here's the really big issue for me with the LC . Seperation of the upper stanchion from the Triple Clamp. Please go read the nearly 4000 posts on Adventure Rider where this issue is discussed. The design is fundamentally flawed and if BMW think that the addition of a stainless steel sleeve will address the engineering inadequacies in this design they are smoking their socks. Every single LC ever built is being recalled . Why?
Because not even Valentino Rossi can keep a bike on two wheels when he has zero steering control which happens when that stanchion and upper clamp seperate. I am frankly amazed when i see a Rider on an LC - I dont care how technologically advanced this machine is - it is waiting to kill you and it seems there are some out there who do not want to or cannot understand this .
Of course BMW is going to do you a deal that appears to be great but they are selling something that is what

??
Keep your twincam. Proven Engineering before the accountants at BMW took over.