Hi and welcome to the forum, pickles!
It's been suggested several times before and the main reason for it not have been implemented yet is that there is no good way to determine if DMA is in PIO mode.
Many times we have told users that they are in PIO mode and they have returned with images from Windows Device Manager stating that they are in DMA mode, so the reason is that Windows can report the devices to be in DMA mode even if they are in PIO mode. So until Microsoft fixes this 'false' reporting - the author has put these suggestions on ice.
You can also get slow speeds with crappy media, so it's not 100% indication to just trust the speed factor.