There isn't necessarily a contradiction there, e.g. you could just see a single ball at any given moment but feel like it was a different ball than the one you saw a few seconds ago. Ditto for the sounds. So you aren't literally seeing anything that isn't there but you may still form higher-level impressions that are not accurate.
The specific visual they’re describing, at least if it was the effect I’ve experienced while actually tripping, is you see the same ball forked into a number of balls that end up merging back together. That was on like 200ug, probably with some cannabis thrown in for good measure.
More broadly you are right, they’re not “hallucinations”. Huge pet peeve of mine when people call them that.
I was telling a friend who’s never tripped on anything about seeing faces in the cliffs. They looked at me like I was stark raving mad and I realized they thought I meant I was seeing a photo-realistic face implanted on the cliff face instead of the reality which was like when (sober) people are gazing at clouds and “seeing” patterns.
Most of us when we are new to tripping make it all about the “visuals”. But the realization eventually comes that in order to get the really crazy visuals your whole reality needs to be tripping really hard and one way it manifests is the visual field. There’s no way to experience “just visuals”, it’s going to come with the bodily sensations and altered temporal processing etc.
I’ve always found it fascinating how people interpret the melting away of time. Some describe it as lasting “forever”, but that’s just the word they’re using to describe the notion that getCurrentTime() is returning null rather than a fixed number.
Hard to explain but something with the brain’s ability to subjectively measure time just melts away and as a result while “physical time” is still marching forward, “psychological time” seems to dissolve. Some people really can’t handle the sensation and freak out.