Are single swarms of Large size completely shapeable in Pathfinder?

Question

This D&D 3.5 question touches on this subject. Recently in a Pathfinder 1e game, it came to my attention that Paizo removed the second line clarifying that swarms were shapeable 10' creatures.

I felt all swarms, including single 10' square swarms, were still shapeable so long as they are either a Line, Sqaure, or Diagonal as shown in this diagram:

Has there been a clarification that swarms are only shapeable if there are more than one swarm in Pathfinder?

I've included excerpts from the 3.5 rules and the Pathfinder rules on swarms.

The 3.5 rules were:

Larger swarms are represented by multiples of single swarms. A large swarm is completely shapeable, though it usually remains contiguous.
...
Unlike other creatures with a 10-foot space, a swarm is shapeable. It can occupy any four contiguous squares, and it can squeeze through any space large enough to contain one of its component creatures.

The pathfinder 1e rules are:

Larger swarms are represented by multiples of single swarms. The area occupied by a large swarm is completely shapeable, though the swarm usually remains in contiguous squares.

Answer 1

The single swarm occupies a 10 foot square (or cube)

The text of the swarm subtype says:

A single swarm occupies a square (if it is made up of nonflying creatures) or a cube (of flying creatures) 10 feet on a side, but its reach is 0 feet, like its component creatures. [...] A swarm can move through squares occupied by enemies and vice versa without impediment, although the swarm provokes an attack of opportunity if it does so. A swarm can move through cracks or holes large enough for its component creatures.

There is no language there that states the swarm can change the shape of the area it occupies, other than that it can squeeze through narrow openings, so a single swarm would always occupy an area (or cube) with 10-foot edges, and could not reshape to, say, a five foot times 20 foot area.

There is no need for a clarification here. The rules are clear, even if they are slightly different from 3.5e D&D rules. Granted, these systems are very similar, but asking for a ruleset to actively explain or clarify in the rules text how it differs from a ruleset by another publisher is probably not something that is reasonable to expect.

Answer 2

According to the rules, there really isn't such a thing as a "Single Large Swarm".

Your original excerpt mentions the following:

Unlike other creatures with a 10-foot space, a swarm is shapeable. It can occupy any four contiguous squares, and it can squeeze through any space large enough to contain one of its component creatures.

This text is also consistent with the later pathfinder text, which also states that as long as a swarm's creatures share a border with one another (IE, Contiguous) that they can be reshaped, regardless.

Both also state the following:

Larger swarms are represented by multiples of single swarms.

Which means, when breaking it down, there's not really a such of thing as a "large single swarm" according to the rules here.. as all larger swarms are just composed of smaller swarms.

Both systems also clarify that large swarms are just clusters of smaller swarms which can naturally be extrapolated as size categories increase. A huge swarm consists of many smaller swarms that would take up 9 contiguous squares. A gargantuan swarm? 16 squares. Colossal? 36 squares.

Each of these is a swarm of smaller swarms.

And per the text, those swarms are completely shapeable as long as it is in contiguous squares.