Spritzbeginn has changed after 20,000 km, is this normal?

Hi everyone,
I was a bit surprised yesterday when I checked my engine data periodically. About 20,000 km ago, I had the timing belt replaced, and at that time, the timing checker showed a deviation of around 55-56. Yesterday, he showed me a starting point of 49-51.
Do I need to worry? Is it normal for the belt to stretch over time, or do I have a problem? Actually, I thought the tension from the rope should be compensated for by the tension roll.
Could it also have been due to the very high temperatures from yesterday? Ambient temperature of approximately 28°C. In the timing checker, the temperature was displayed as 160.

Greetings
Reuselkopp

It is normal that, at high fuel temperatures, it takes longer, because the fuel expands and becomes more compressible.

I would also like to know whether the stretching caused by the clamping roll is being compensated for. Actually, I thought... not

Malte1408 wrote:

I would also like to know whether the tension from the winding roll is compensated for. Actually, I thought... not

It's not balanced because the tension roll is sitting in the empty drum(?)

However, the synchronization between the KW (main line) and the NW (secondary line) runs through the front section -> if the ZR (secondary line) is delayed, the NW is also delayed relative to the KW.