I once had a tiler explain to me that this is how you do it with these long formats because tiles never end up perfectly straight but form a hump. With long formats, this naturally creates an extreme difference towards the edges, and if the tiles next to each other have too much offset (in the extreme case 50% offset), the highest point of the hump of one tile comes next to the lowest point of the next, which can even become a tripping hazard.
That’s why the offset is not made that large. It was also written on my tiles. Maximum 20% offset.
Here it looks more like 10%, maybe ’s tiler is just very careful or the tiles are very crooked.
The fact that you don’t always make the exact same offset has to do with the wood pattern, then it looks more "natural".