There is not one Great Table. There are two, and the difference has divided practitioners for over a century.
The first was produced during the work of 1584, with Dee present and recording in his usual manner. Three years later, in 1587, Edward Kelley working alone produced a revised version, now generally called the Tabula Recensa or Reformed Table. The revision changes the positions of the four Watchtowers within the table and alters a number of letters. Dee accepted it.
The consequences are not cosmetic. Because the angelic names are read out of the letters, a changed letter changes a name, and a rearranged tablet changes which element a given name belongs to. Two practitioners working conscientiously from the two tables will address different entities in different quarters.
The circumstance of the revision is uncomfortable for anyone hoping to settle the Kelley question. The one substantial alteration to the system's central artefact was made by Kelley at a point when Dee was not observing, and it arrived after the relationship between the two men had begun to deteriorate. That is a fact about the record, not an accusation; it can be read as evidence of fabrication or as evidence of nothing much, and the literature contains both readings.
The Golden Dawn used the Reformed Table, and most twentieth-century practice follows it for that reason rather than on any independent judgement. A visible minority of modern workers, associated with the movement to return to the manuscripts that gathered pace in the 1980s and 1990s, prefer the 1584 table on the grounds that Dee witnessed its reception. There is no way to adjudicate between them from the evidence, and both camps know it.