“However, on no occasion in the Old Hieratic palaeographic record do we find a cardinal number ∩ rotated 90 degrees from upright that is not a date.”
What he cites for this is Goedicke’s Old Hieratic Paleography, evidently making the dubious assumption that Goedicke’s palaeography is (or would claim to be) comprehensive. Some will remember that Creighton chose not to mention this to his readers:
The status of the numerals is unclear, but they are not explicitly a date and they are rotated relative to the rest (but let’s not go confusing the reader with evidence).
“Given the total absence of the solar disc sign from all of the number signs in Campbell’s Chamber (Figure 5d), it is highly unlikely that these signs represent calendar days, as some have suggested.”
Who has suggested? We are not told. What he cites for this is Plan XII in Reisner’s Mycerinus, but that is merely the source of the illustrations. Again, in the discussion of this material (Appendix E), there is no such statement. We are left with the impression that Creighton has made it up.