According to https://en.wikipedia.org/wiki/Hewlett-Packard_9100A
The Hewlett-Packard 9100A (hp 9100A) is an early programmable calculator (or computer), first appearing in 1968. HP called it a desktop calculator because, as Bill Hewlett said, "If we had called it a computer, it would have been rejected by our customers' computer gurus because it didn't look like an IBM. We therefore decided to call it a calculator, and all such nonsense disappeared."
How long did this marketing trick need to continue? I would expect only a few years; by 1975, the Altair 8800 was being openly sold as a personal computer, its development driven precisely by the bottom falling out of the calculator market, causing MITS to try a desperate pivot. But did the marketing trick end closer to the beginning of the seventies, or the mid-seventies?
Edit: Here's another source with a comment about the marketing issue: http://www.hpmuseum.org/hp9825.htm
The "calculator" label was also clever marketing because US Department Of Defense procurement regulations (and some company regulations) made it a lot easier to get approval to purchase a "calculator" than a "computer".