Smokey, thanks for your answer.
Finally i read and read it through but there is still that strange thing:
Once you get these new V1 and Vr values, you still need to check them versus your runway performance tables ( for any given or individual airport) right? If you find a lower V1 for the actual temperature and actual weight, then you cant flex at all. But this can only be a problem when field lenght is limiting factor. The lowest V1 found is still ruling isnt it? E.g.: OAT 30°C. Standard speed is 130 for V1 and Vr at a given weight. Now Rule says increase V1 and Vr by 1 knot every 5°OAT above 30°C. Meaning a flex 50 needs a speed increment of 4 knots on Vr and V1.
Now i have a look into the runway table and find lower speeds for V1 and Vr at 50°OAT or assumed OAT. (assuming the weight is just correct with what ive git on my loadsheet, which is seldom, i know) Which V1 shall i take then?
Another thing a bit off topic. Is it right that flexing below 30°C is not allowed because it is the flat rated temperature?
regards
Leo