Expanding the subject to why row numbering isn't necessarily consecutive

Theory 1: Avoiding renumbering should F/J/Y seat counts change.
Using a B747 for example, there are many sections if you think of the doors as natural partitions. Some airlines intentionally have large gaps between the last row of one section and the first row of the subsequent section such that if the former section is reconfigured to have an increase in the number of rows, the subsequent sections don't have to be renumbered.

e.g. In the B744 of NW, the section between doors 2L/2R and 3L/3R used to have a mix of C and Y seating. A few years later, it was reconfigured to just have Y.

e.g. Perhaps there used to be a row 1, but it was eliminated when a bathroom or closet was added. And, the airline didn't want to deal with renumbering the rows.

Theory 2: Low numbers are only used for a given premium cabin

e.g. In the regional (intra-Asian) 777s that CX operates, there is no first class, only business class and coach class. The first row number is actually 11, situated in the J cabin. In intercontinental 777s where there is a first class, the first row number is 1, situated in the F cabin.