Question [Q] Cpu Min Fruequency Not Stick (Even i didnt Reboot yet )

i buy a Galaxy Grand 2 SM-G7102 ..Grand 2 is a great phone... and i installed Custom TouchWiz / Prerooted Rom on it .. but.. when i use all cpu app on play store Even Setcpu ,i cant even change or stick the min to EX:1.12 Mhz ... i try the max and it work... so just the Min... and maybe.. can you help me with this... because i want to make profile in screen off to save power .. like that .. so dev.. hope you can help