Draft Curtains, Sprinklers for Vertical Opening?

I am working on a project with non-enclosed vertical floor openings, approximately 6-ft by 10-ft. Looking at FMDS (Factory Mutual Data Sheet) 2-0 and NFPA 13, I found similar language that I need help understanding.

FMDS 2-0 2.5.1.7.4.1: A non-enclosed vertical floor opening does not need a combination of draft curtains and closely spaced sprinklers if

• (A) The floor opening joins spaces/floor levels that are protected by ceiling sprinklers in accordance with FM Property Loss Prevention Data Sheets, 
• (B) The horizontal distance between opposite ends of the opening is a min. of 20 ft (6.1 m) in all directions, and
• (C) The area size of the opening is a minimum of 1,000 ft² (93 m²).

(B) seems to contradict (C) as I read it. (B) seems to be describing an area of 400 ft², which leads me to believe I am misunderstanding something.

NFPA 13 words it differently, but it still didn’t click.

NFPA 13 2022: 9.3.5.4 Large Openings. Closely spaced sprinklers and draft curtains are not required around large openings such as those found in shopping malls, atrium buildings, and similar structures where all adjoining levels and spaces are protected by automatic sprinklers in accordance with this standard and where the openings have all horizontal dimensions between opposite edges of 20 ft (6.1 m) or greater and an area of 1000 ft² (93 m²) or greater.

How should the 20-ft horizontal dimension requirement be interpreted, and how does it work together with the 1,000-ft² minimum area requirement without creating a contradiction?​

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