Comma use

Hi. I was searching for some help on comma usage online and found this. In THE OWL AT PURDUE, OWL MATERIALS From the OWL resource Commas, under the section named "Extended Rules for Using Commas," in rule 2 titled/named "Use commas after introductory a) clauses, b) phrases, or c) words that come before the main clause," under its 2b, I saw this (as written):

b. Common introductory phrases that should be followed by a comma include participial and infinitive phrases, absolute phrases, nonessential appositive phrases, and long prepositional phrases (over four words).

Having finished the test, he left the room.

To get a seat, you'd better come early.

After the test but before lunch, I went jogging.

The sun radiating intense heat, we sought shelter in the cafe.

My question: Do the words/phrase in parentheses, "over four words", apply to all just (previously) mentioned phrases in the same sentence?