It's a bit misleading, that one, isn't it? Going across, you get younger generations, but going downwards you find older ones - aunt/uncle, great aunt uncle etc. Yet the leftmost column lists child, grandchild etc when logically it should list parent, grandparent to fit in.
What some folk seem unaware of is that "once removed" can mean going a generation either way, and it's not specific. You could have two such cousins two generations apart (I do!) and a pair of cousins twice removed could be four generations apart!
My last surviving older first-cousin-once removed is first-cousin-twice-removed to my younger first-cousins-once removed.