I think you are all too hang up in the "as good as last rally" and tire choices.

Yesterday Mikkelsen and Loeb were only ones on same tires and were at same pace, quite far off the others on other tires.

Today Mikkelsen has similar speed as he had on Monte last year. I20 works well on bumpy and slippery/tricky tarmac, while it works quite bad on smooth/high grip tarmac (Shakedown here, Spain, Corsica, most of Germany).

So while he did good today it's not really much of a change.