Does Signpost 4 cover the crisis decision and climax of the story?
First, it depends on how you define "the crisis decision and climax of the story."
Since there are are four Signpost 4s (one in each throughline), how Signpost four fits into this can be seen in a number of ways. The end of all the signpost fours signals the end of the problem-solving cycle. It is either resolved or unresolved, satisfactorily or unsatisfactorily. The "crisis decision and climax of the story" should happen sometime before all four signpost fours are completed. Sometimes an author chooses to time the resolution of all four throughlines such that they occur simultaneously.
Sometimes an author chooses to stagger the resolutions of the throughlines such that they happen independently, spread over a period of time. Sometimes an author chooses to combine the resolutions of some throughlines but stagger the others.
I believe this is important to point out because my interpretation of "crisis decision" and "climax of the story" is that they are two different events that may, or may not, occur simultaneously.
By "crisis decision," I assume you mean a point where the Main Character consciously makes a "leap of faith" choice either to stick to her chosen path (Steadfast) or to chuck it and adopt an alternative path (Change) [NOTE: This ignores the non-leap of faith type of story, but that is not important for this analysis.]. IF this is the case, then the "crisis decision" could be defined as the end (or resolution) of the Main Character Signpost 4 (as well as the end of the Main Character Journey 3).
By "climax of the story," I assume you mean a point where the attempts to reach the Story Goal in the Overall Story reaches the maximum limit (time or options) bringing about the final confrontation between the forces for and against the story goal. IF this is the case, then the "climax of the story" could be defined as near the end of the Overall Story Signpost 4 (as well near the end of the Overall Story Journey 3).
It is possible, however, that by saying "the crisis decision and climax of the story" you meant the point where all four throughlines came into sync just prior to the resolution of each throughline and therefore create a last gasp surge to resolve the story inequity. If this is what you meant, then it would be safest to say that it happens near the end of the four Signpost 4's.
In each case, the resolution usually describes the bit AFTER the "crisis decision" and "climax of the story." The resolution is the aftermath of the conflicts and is usually the very last part of each throughline.
From a storyweaving perspective, the resolution of each throughline is often delivered in a post-climax, and seemingly post-story, epilogue or denouement. This is a scene where how things ended up are described to the audience.