Using supports under a slideout, will void the warranty, if you end up with problems.
Slideout supports are holdovers from the early days of slideouts, when the technology was new and problematic.
Every RV manufacturer I know of, says never to use them.
and Zoe the Wonder Dog(R.I.P.)
'07 Roo 23SS pushing an '07 Chevy Avalanche
Equalizer WDH and Prodigy BC