Why set PATH doesn't work?

Question

cmd/bat

Answer 1

setx /M PATH "%PATH%;C:\Windows\twain_32\CNQL25"

for /f "usebackq tokens=2,*" %A in (`reg query HKCU\Environment /v PATH`) do set save_temp_path=%B
setx PATH "%save_temp_path%;C:\Windows\twain_32\CNQL25"