Evidently pi 1707/pi 1709 rather than pi 1708.
The lexicographer probably has something in mind like the grammarian Dionysius Thrax' assertion that the adjective *platw/neios, as here, should refer to the man Plato or something of his but the adjective *platw/nikos should refer to something about Plato. See Scholia Vaticana in Dionysii Thracis Artem grammaticam, p.224, l. 7. Be that as it may, TLG searching reveals that the form *platw/nikos is vastly more common than *platw/neios and that the alleged discrimination in use cannot be demonstrated from the Greek passages.