The series as it stands is a first millennium standardisation, and it is not a single composition. Tzvi Abusch's critical edition, published in 2016 after decades of work, rests on the argument that Maqlu grew: an older stratum of independent anti-witchcraft incantations was gathered, arranged, and then supplied with the ritual instructions that now bind them into a night-long sequence. Where those layers meet is visible in inconsistencies of address, in incantations that assume a different setting from the one the ritual tablet gives them, and in the varying relationship between an incantation and the action attached to it.
That argument matters beyond this one series, because it offers a model for how Mesopotamian ritual literature in general reached its canonical form. A text that looks like a designed whole may be an assemblage that acquired its design late, and the parts may be considerably older than the arrangement and may originally have done a different job.
It also changes what the series is evidence for. Read as a unity, Maqlu testifies to the beliefs of the first millennium scholars who fixed it. Read as a stratified compilation, it testifies to a much longer development, and the anxieties in its oldest layers are not necessarily those of the men who copied it into Ashurbanipal's library. The atlas records the series as attested and the reconstruction of its growth as scholarship, because the reconstruction is an argument about the text rather than a fact recorded in it.