Petrie was, however, quite vehement in his view:
"On the monuments bearing the name of Khnumu-Khufu at Gizeh, and at Wadi Maghara, there also occurs with different titles, the name of Khufu himself. That the names should thus be found together is very likely, if they were co-regents, as their joint occurrence in the Pyramid would lead us to expect.
The choice, then; lies between the simple idea of a co-regency, such as we know often existed or else, on the other hand, adopting a late pronunciation, ignoring one character of the name, inventing the application of prefixed determinatives in cartouches, and supposing that the King's name would be put in duplicate on public monuments with and without a determinative. These requirements are contradicted by the well-known usage found on all other remains."
(Taken from: The Pyramids and Temples of Gizeh by WM Flinders Petrie - Historical Notes")