Unlike a printed book, a classical Sanskrit treatise such as the Phaladeepika survives as a manuscript tradition, copied and recopied by hand across many centuries, and a text transmitted that way rarely carries a fixed, unambiguous date of composition the way a modern publication does. Colophons naming a scribe or a patron can date a single copy without dating the original composition behind it, verses attributed to a named author can be added or dropped between recensions, and later commentators sometimes rework the surrounding material enough that dating the commentary tradition and dating the base text become two separate problems. This is the ordinary condition of classical jyotisha literature, not a defect unique to this one book, and it is why a genre survey of the kind this atlas cites for the Phaladeepika treats textual dating as one of its central, recurring problems rather than a settled fact to be looked up.
The consequence for a reader is straightforward and worth stating plainly rather than papering over: this atlas records Mantreswara's authorship as the tradition's own settled attribution, but it does not assert a specific century for the work, because the scholarship it draws on does not agree on one. Proposals in the literature range across roughly three centuries, from as early as the thirteenth to as late as the sixteenth. Where the Brihat Parashara Hora Shastra's own entry on this atlas notes an open question about when that earlier, foundational text reached the form now studied, the Phaladeepika sits downstream of exactly the same kind of transmission history, and the honest position is to say so rather than to pick a number that no single source actually supports.