While I have no experience with Kioti, I suspect what you are experiencing is normal operation. If you run a Kubota loader for any length of time, you will be disappointed with most other compact loader valves. John Deere CUTS/SCUTS have almost no 都weet spot for getting two loader functions to operate simultaneously either.
Agreed, It's not a defect, it's just the way the tractors were designed. Cheap and cheerful.
I think you will find that more SCUTs/CUTs can't do two functions simultaneously than can. FYI some older tractors had no down pressure on the loaders - they relied on gravity.
Generally larger tractors have more hydraulic flow and can do two functions at the same time.