I purchased a used 2012 Volt, and I found that it does not offer an option to "Change Charge Level" - there is no option to choose 8 amps versus the default 12 amps. The manual notes that only some models have that feature. Is anyone aware of an upgrade, software or gulp hardware, that would allow me to the option to change the charge level? If not, any recommendations for low cost EVSE equipment that could let me do the same? Here is a photo of my screen and a photo from the manual with the option shown.