I think it was definitely played most on the North America leg.
In my mind it certainly wasn't a regular in the set, albeit I agree, it pops up on other legs from time to time.
The repetitious solos I'm talking about are the songs that go back further. The solos evolved over several tours, they evolved less from week to week on the 92 tour.
I checked On Every Bootleg site
The '91 european leg is featuring 32 gigs recorded panning from 23rd August 1991 in Dublin to 14th October 1991 in Zurich
PONO appear in 100 % of the recordings
Always performed on the first quarter of the show.
Fifth position is usual number - and I would say it was 90% of the time.
When not in fifth position, it was between the third and seventh position.
We have only two recordings from the down under leg, PONO was still there.
For the '92 US leg 27 gigs are featured
For the first 16 available recordings, PONO appear 15 times always performed in fifth position.
The only recording where PONO is not featured is said being the full show - third US recording - 5th February 1992 - Sports Arena, San Diego, USA.
The 17th recording (2nd March 1992 - Spectrum, Philadelphia, USA) is very partial show and do not feature PONO
The last ten recordings are full or almost full.
From 4th March 1992 - War Memorial, Syracuse, USA to 4th April 1992 - Center Coliseum, Seattle, USA
PONO is performed 6 times
The first two ones at the usual fifth position
The las four ones at various position within the third quarter of the show (ie between SOS and TYL).
Then the 1992 european leg where it was still on the setlist but more and more on a random basis.Edit : I checked and only available recording is Paris April 27.
I still mourn missing the '91 leg because PONO is my fave song of the show and I feel sooooo unlucky only witnessing PONOless gig in '92.