best try your setup + any memory bench - HWINFO log
find problem “why is limited” and how it currently system works around the limit. “i think you run on max”
also M.I.T. contains some special items for memory “I don’t know what they are doing”
moreover, I last used such a high voltage as you require with DDR3 
or like this “on notebook” - all this limits external EC CHIP
in your case it may be the preset fw in chipset or EC or on DDR or mobo design
unfortunately I do not know 
.,.above is a list of domains I would check “for advanced RAM setup”