It is indeed (well on some regions, not all) and is most likely a placeholder.
As I have already said, no cross generation title released has had the same install size on both platforms, with PS5 titles being between 30% and 70% smaller. Due to two factors, one being how high speed SSD's function, meaning you don't need to duplicate assets for streaming purposes, and the other being the Kraken compression that is unique to the PS5.
As such two options exist, either the PS5 install is 110GB and the PS4 one is bigger, or the PS4 install is 110GB and the PS5 one is smaller. Given we know what GTS clocks in at, the 110GB is most likely to be for the PS4 version.
Dirt 5 being a racing title is perhaps our best/only guide right now and that clocks in as follows:
- Dirt 5 – 50.9 GB PS5 vs. 63.3 GB PS4
I'm dismissing the third option of them being the same, as it would mean PD having to actively ignore two key features of the PS5's core architecture and actively work around using them for no good reason at all.