Xamedhi it's all falsetto (not adducted vocal chords). I could do similar sirens high up on my very first day very easily but when I tried to sing say a g4 in headvoice for example it was impossible. Try this. Try going up high on a siren and when you reach the peak open your mouth and sing "this is my headvoice" all at the same pitch. Recored it, it will be falsetto. Don't get me wrong I think falsetto is great, I train my falsetto every day because it helps build my headvoice. It's the gateway to head voice. Believe what you want, I am not trying to get you down or disparage you, I am simply making an objective observation. Knowledge is power.