A coin toss did not determine Iowa.

First the tosses pick county delegates, not state delegates county delegates are not nearly as valuable.

In addition:

The state party doesn’t track all of the coin flips, but following anecdotal reports of Clinton’s improbable luck on Monday night, Lau disclosed that it was Sanders who fared better in the games of chance that were reported through the party’s official mobile app. The Vermont senator won six of those seven coin flips--a fact that underlines how incomplete the available data remains, and the likelihood that a full accounting of all the coin flips on Monday night would yield a more even result than initial reports suggested.