Well The BIOS shows % as well, but in volt format. .63% to be exact of Vtt for MCH ref unless you deviate from that percentage

Please do notice that at 1.20 Vtt stock, MCH Ref and CPU ref for example are .76 same as you would see in ET, which is .63% of Vtt. You have to keep the default % values in mind

As for your question about the above, with .76 showing in the ET Screen and 1.34Vtt, the BIOS MCH Ref could be set on Auto or it would be manually set at .8442