Hi,
I didn't get a different binary (at least, using this method) when charging the battery, nor did I get different results when doing so under full CPU load under linux.
Getting frustrated with the livecd I took a break and tried Hardware Monitor under windows. The "GPU voltage" was static at 1.062 V while charging the battery and under none-to-light load. (graphics and memory clocks at 351 and 800 MHz respectively) The CPU voltages started to swing noticeably when the CPU was stressed, but the GPU voltages remained constant. This was confirmed by AMD OverDrive. (version 4.2.6.0659)
However, when stressing the GPU using a browser-based benchmark ( web.basemark.com), the GPU voltage spiked to as high as 1.137 Volts as reported by the windows software. I switched back to void linux and ran the same benchmark, but unfortunately the collected vgabios rom is still the same. (even while under such heavy load that the computer became difficult to use)
Sincerely, -Matt