I tried the same thing you did back when I found the Advantech BIOS, and then realized why it did not work. There may be other causes but the biggest reason is that the VGA module within the BIOS is different. Even if it is for the same video chip, how that chip gets set up to drive a CRT or LCD display is different. The various LCD displays are far from standardized so it is very likely the VGA module of the IO BIOS has setup routines unique to the IO and its LCD video display.
I took my test one step further and extracted the VGA module from a 10/99 IO BIOS and replaced the VGA module of the Advantech BIOS with it. I flashed this to the IO and tried to boot. Unfortunately it still did not work. I figured it would be a long shot, and it was.