The Decision spread is a modern topic layout of unrecorded authorship, and its structure makes an assumption that is worth stating before it is used.
Provenance
Two-option comparison layouts appear widely in twentieth-century and later tarot handbooks with varying position counts. No first author can be identified, and the atlas records the authorship as unknown rather than supplying one.
The assumption in the structure
Two of the five positions stand for option A and option B. The layout therefore cannot represent a third course, and cannot represent doing nothing, unless the reader deliberately assigns one of the two positions to it before dealing. A querent who arrives with a genuine binary is well served. A querent who has framed a wider situation as a binary will have that framing confirmed by the layout, because the layout has no way to question it.
This is the general hazard of topic spreads stated in its sharpest form: a spread encodes a model of the question, and the model is chosen before any card is turned.
The fifth position
The remaining positions describe the situation, what the querent has not considered, and a recommended course. The fourth of those is the one that can break the binary, since what you need to know is the only position in the layout not tied to an option.
The atlas records the positions separately and describes the practice rather than instructing in it.