Combat techniques include blood circulation techniques in them. However, not every body had the same type of body.
While one's main artery might be in the same place, a specific set of vein needed for the blood to flow through to activate the technique might be in the place of a different spot and then replaced by a useless one.
This is why several sets of separate veins are imprinted in each techniques. If it doesn't work the first way, try the second circulation method, they give the same output anyways.
Moreover , Tyrion had reached the Ultima state in the techniques, making him extremely familiar with the techniques. The ultima state meant that he possess about a hundred years of experience in the techniques and could easily manipulate them as he wished to give the same result.
At first, Tyrion didn't see the need for it and had thought it wasn't anything much.
Now, he knew how big of a deal it was.
