Reading Mark Hennessy post above they work differently, and from my post, my photo and the photos usually found about everywhere there are at least two different silk screens.
I think that what happened may be:
1) they design the correct multimeter with correct firmware and front panel graphics and they sell the first batch,
2) later, somebody make a mistake in programming a lot of said meters, enabling Hz and Duty Cycle on V position,
2b) they sell them , including one to Mark Hennessy,
3) customers complain and the Boss call Enginereing
4) two decisions are taken: a: program new boards with correct firmware and b: design and print modified panels for already programmed boards in stock
5) somebody in production mixes everything.
I've seen similar stories many times