What "Position in Commercial Break" Actually Means

The "Position in Commercial Break" setting does not restrict an ad to appear in only the exact position specified. Instead, it creates what's called a "Restricted Sequence Variant" that allows the ad to appear in any position up to and including the specified position. 

For Example,

If you set "Position in Commercial Break: 3" - the add can appear in positions 1, 2, or 3, but not beyond position 3.