The running order had been unclear for over three hours due to problems with new provider SIT's timing system on stage three.
When accurate results were eventually published, teams' estimates that Loeb now held a 1m20s advantage proved correct.
The world champion, who is only contesting four rallies this year, was quickest by 12 seconds on SS3 and 34s on SS4.
In tricky half-ice, half-dry conditions, Loeb found far more confidence than his rivals.
Although nearest pursuer Sebastien Ogier lost over a minute to Loeb, he still holds second for Volkswagen.
Mikko Hirvonen has progressed from seventh to third ahead of Citroen team-mate Dani Sordo, despite hating the conditions. But the Finn remains 26s off Ogier.
Jari-Matti Latvala raised his game considerably in the afternoon as a set-up change increased his affinity with the VW Polo.
Only 10th after the first loop, Latvala had shot up to fifth by the end of the day.
Evgeny Novikov is now the top M-Sport Ford driver in sixth, just ahead of 2011 Monte winner Bryan Bouffier and Novikov's team-mate Juho Hanninen, who felt he had been too cautious.
Thierry Neuville, another M-Sport runner, was the first frontrunning retirement, dropping out of fifth with a mistake on stage four.
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- Sebastien Ogier