Hi Debanjan,
If I am not mistaken and remember it correctly, I have such a problem of “not changing Q-factor” couple times. As Alistu recommended, I did increase the range of my power set and that gave me Q-factor dependence. At the same time, I would recommend you to look at the regime that you are working at for your launched powers. It is know that high values will increase the influence of non-linear effects in your system.