This is a bit obtuse for the sake of pedantry.
I mean, is it possible that you could build a device resistant to submersion but not splashing? Maybe?
But this isn't "a device", this is a phone. The problems with water ingress are very specific. You have a couple of speakers, a few microphones, a sim card slot and a USB port, plus the seams for the screen and backplate. If you secured those well enough for the immersion tests they're going to be splash-resistant. If you have a way in which you can somehow have a phone screen adhesive survive being underwater for several minutes but not falling rain or being placed under a tap/hose please do share, because I can't think of one. The scenario where your speaker seals are good enough for being fully submerged but get water damaged by shooting high pressure water directly into them is so niche it's probably not worth it to further confuse people by having two different IP ratings listed.
Plus... you know, don't be shooting water hoses directly up your phone's holes regardless? I don't see why you would in the first place, but... just don't? It's not gonna happen by accident, so it doesn't need to happen at all.