So the way the Ford / Lincoln extended bumper to bumper warranties work is that as long as the vehicle is under the factory bumper to bumper warranty, you can add extended coverage with no problems. If the vehicle has gone out of the factory bumper to bumper coverage, then before you can add more bumper to bumper coverage, the vehicle must be inspected (so that you cannot sneak in an issue that would have been covered) and the service shop has to sign off that the vehicle qualifies for the added coverage. So, as long as your vehicle has no issues, you should be able to add more bumper to bumper coverage, up to the limit of iirc 60k miles or 4 model years old (on the Lincolns, Fords may be less). On the Lincolns, you can go up to a total of 9 years or 125k miles (from original in-service date) if you are willing to pay for it (typically 6yr/100k or 8yr/125k is the sweet spot in terms of cost on the Lincolns, I don't know on the Fords since they are priced differently) but on the Fords that is somewhat shorter and I don't know the exact limits because we do the Fords much less often.
Now you didn't get this from me, but the dealer's cost for any of the extended warranty stuff is roughly 65-70% of the suggested retail, so you should be able to get 20-25% off the "retail" price if you negotiate carefully and politely with the dealer still making some money. You may have to say "no thanks" the first time and call back later to let them know you want it, but only at the right price. And it will depend on the dealer - some are much more flexible than others.
Typically, prices change twice a year, and the last price change was last fall, so March may well be time for a price increase.
If you need more specifics, I can look up the Ford premiumcare details.
