Figured it out
sata_args is only used for VMWare/ESXI booting.
If you look at the loadlinux function in grub.cfg it passes bootdev_args to the kernel. bootdev_args is evaluated using
eval "set bootdev_args=\"\$${bootdev}_args\""
bootdev is the 2nd value passed to loadlinux and is "usb" for Baremetal and "sata" for VMWare/ESXI.
So sata_args is only used for VMWare/ESXI and will have no impact on Baremetal.
If you want to play with SataPortMap (which works perfectly for Baremetal BTW) then add it to "extra_args_3615" (3617, etc.) so that you're not modifying "common_args_3615".
Hope this helps ...
Berardino