I am about to install k-tech valves in my forks in the next few days. I will let you know how things will go and if I get the same feedback with the stock springs. Hopefully not, as I was looking to eliminate the stiffness of the standard valves and not increase it.
One thing comes to my mind, according to some k-tech documentation the oil level with the valves should be 150mm, which means 2cm less oil than standard and even less than the hyperpro recommended level which I think is 125mm from the top. Maybe this is worth checking.