In James Joyce's "Ulysses," Stephen Dedalus says, He's playing around with perception and dimensionality, messing with our minds.
Some of the hexagram readings by different characters are linked in ways that they cannot know - only the reader from outside the meta fiction could see the pattern. I've written more on the meta-fiction's relation to the I-Ching here, and cited every one of the hexagrams mentioned in the book. In this case, however, he’s tied his metafiction to a 3,000 year old book that exists in our world and imbued it with a power to glimpse beyond the fourth wall. Dick: think of Dekkart not knowing if he’s a replicant or not in Blade Runner/Do Androids Dream of Electric Sheep or the layers of ambiguity about what’s real in Total Recall/We Can Remember it for you Wholesale. This is irresistibly delicious stuff, classic Philip K. But if that alternate history is real, then the upward implication from book within book to reader is that we ourselves live in a fictional construct - one which might betray its fictionality through consulting the I-Ching for a window on the next level up. But the fictional construct of the world in The Grasshopper Lies Heavy is not in fact the world in which we and the author live - it’s similar in the outcome of the war, but diverges: FDR’s adviser Rexford Tugwell succeeds him as President, and the Cold War is between the US and an intact British Empire instead of the Soviet Union. She does, in fact, occupy a fictional construct created by Dick - which he constructed by consulting the I-Ching.
Juliana interprets the hexagram to mean that The Grasshopper Lies Heavy represents the truth - that Japan and Germany lost the war, and she inhabits a fictional construct.