Another map appears in Charles Hall's definitve history of Sheffield Transport ALSO dated in 1927 - this time with the month June added. And this time the tram routes to Crookes and Walkley (thin lines with bobs on the end) are correct! Inconsistency rules OK; even under the tutelage of the great ARF.
Perhaps, as a good friend opined, the official line then was "if it's on the engraving it must be right" as, similarly today, we are offered the explanation "well, that's what the computer says". At least we now know that the celebrated A R Fearnley's team wasn't always perfect. That may give a little comfort to his 21st century successors.