Google chain stretch for that model. I think I read about 10° also.
Your car may be serviced but they only do whats on their list (if you are lucky) and checking the timing chain stretch is not one of the items, though given the history of chains on sub 2013 models then it doesn't take much to check if they have their laptop plugged in to reset your oil counter when the engine is up to temperature.
I normally have that PID saved along with Fuel Dilution, Number of Regens, Battery SOC as when I go for fuel take those readings with mileage, and the dash mpg and log it in my ruled notebook as the car is usually up to temp at that point.
What you have to decide is if the chain snaps what is the cost of damage (new engine) or have it changed before damage is done.
There has been many cases of timing belts and recent chains (after it was decided to change back but to fit necklaces rather than a decent heavy duty chain) letting fly and bent valves, holes in pistons ensuing from the wreckage. The engine may still run ok but whats the longevity of the chain. You pays your money, you takes your chance.
My brother has just changed the chain on a 1932 Daimler 15 (hp), it was a double widith chain and they used the dynamo to tension it. There was no more adjustment on the dynamo. When the timing was checked it was way out but I assume the engine still ran at some point. He managed toget 30 psig oil pressure turning it over on the starter motor and compression pressures 50-100 psig, so a runner. He just has to make sure the block is sound and no cracks on the water side.
Engines may run with a stretched chain, but how efficient, clean and does it start easily.
