NOTATIO

Ooh, I find that very confusing.

In your example, there's nothing to indicate that it's different from a normal bar number in any way. At least on mine, it's in brackets.
So it would be very easy to read that 'end' of the cadenza as "bar 35".

Yes, their system us confusing in either case. I prefer the style that places such bar numbers at the beginning of the first complete measure in the system.