C2/3 CE. See generally OCD(4) p.7, under 'Achilles Tatius(1)'.
A majority of the manuscripts and Byzantine references give Achilleus Tatios as the name of the novelist. Tatios might be a transcription of the Roman name Tatius. On the other hand, considering that Achilles was Alexandrian, Tatios might be a theophoric from the Egyptian god Thoth, Greek Tat. The initial sigma in the Suda's 'Statios' resulted from doubling the final sigma in the preceding word, Achilleus.
[1] Also identified as an Alexandrian by Eustathius on Homer's Odyssey 14.350 (vol. II, p. 73) and Photius, Bibliotheca cod. 87 (p. 66a.14). This is perhaps supported by the high degree of topographical realism in a passage in the novel describing Alexandria (5.1-2).
[2] Presumably this means late in his career. In any event, unlikely to be true (OCD).
[3] Extracts from an astronomical treatise have been transmitted along with the text of Aratus under the name Achilles (E. Maass ed., Commentariorum in Aratum reliquiae [Berlin 1898] pp. 27-75, 80-85), whom Firmicus Maternus regarded as "the most sage Achilles" (prudentissimus Achilles, Mathesis 4.10). OCD(4) p.7 lists a separate 'Achilles Tatius(2)'.
[4] The translation of the final sentence is debated. An alternative would be "His style in all his works is similar to [the style in] other writers of love stories," or, even less likely, "His style in every respect [or, "everywhere"] is similar to [the style in] other writers of love stories." The Suda is evaluating the consistency of the novelist's prose style throughout his obviously varied corpus. The translation here concurs with E. Vilborg (Goeteborg 1962) 9 (cf. n.10) and K. Plepelits (Stuttgart 1980) 1; the Budé editor offers an alternative translation (J.-P. Garnaud 1991, vii, n.2).