AUDI A3 8PA 2011 1.6 TDI 77 KW CAYC

Hello, I have an AUDI A3 8PA 2011 CAYC engine with VDO siemens piezo injectors. I wanted to know how to properly check the injectors‘ performance/work, because I have a very good OBD reader for that, which shows the injectors' performance (mg/stroke) cylinders injection quantity deviation, but I just don't know how to check it correctly. Should I check on a cold engine at idle (neutral), on a warm engine at idle (neutral), or even while driving?

Maybe you know what the +- mg/stroke should be with my injectors in each injector and with what values ​​​​it is already necessary to do a restoration, and when a simple cleaning is enough.

I hope you understand what I am trying to achieve with this post. In general, I want to know how to check the injectors (in what position and for a cold or warm engine), what the values ​​of +- should be and when to do a restoration or cleaning. I can send what OBD shows in current time.

If you have anything to mention or add, I will be happy to listen. Big +aura and +respect to everyone who helped.

Currently, at cold idle when it worked for like 5-10 min the results are:

Cylinder 1 injection quantity deviation: -1.09 mg/stroke;

Cylinder 2 injection quantity deviation: +0.34 mg/stroke;

Cylinder 3 injection quantity deviation: -0.15 mg/stroke;

Cylinder 4 injection quantity deviation: +0.62 mg/stroke