We now know the underwriters did, in fact, exercise the overallotment. There was no public offering price to defend here, I doubt any shares were actually sold to the public at $17.00. The underwriters were free to short stock above $15.98 and cover with the overallotment.
More generally, in a follow-on offering, where the stock is actively traded and has a market cap of at least $150 million, the underwriters are not subject to the constraints they would be in an IPO. The stock would be an "excepted security." Or at least, so this article says https://www.lw.com/thoughtLeadership/regulation-m-guide-faq
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