No need. From my many trips across the Causeway i've ever used
the card on 160/170 then transfered to 950 & vice-versa &
it works i.e. transfer indicated.
My conclusion is that as long as they use the same system,
irrespective of operator the transfers would be processed as normal
as if you used back the same operator to complete the trip.
Also noteworthy is that of late even SJE started selling tickets
just before passengers board @ the Causeway, making it more
convinent for those who didn't buy them from the travel agents @
City Square or Merlin Tower or Larkin.
It's only a matter of course that they do that if they don't want
to lose out too much to the other 2 operators !!
On the Singapore side @ Woodlands complex noteworthy too is the
fare prominently indicated on the official operator's metal signage
for those wanting to take CW1 from there to Kranji. Currency used
of course then in S$.
From personal observations, it's also routine practice for many
people to board from there only buying tickets onboard as they head
towards Kranji or Ban San etc. whether on 160, 170, 950, CW etc. In
SJE's case, being the only operator without onboard ticketing
machines, people buy the tickets from the SJE ticket inspector
instead. I suppose they need to innovate a bit to survive !