2.1.1436 Part 1 Section 21.2.2.14, bandFmts (Band Formats)

a.   The standard states that bands are indexed from low to high.

The bands within this collection are indexed with increasing index values that correspond to increasing values in the chart.  The lowest index value for a band is 0, regardless of whether it is present in the collection of formatting bands. Bands with no explicit formatting may be omitted from the collection.