5 linking on 5/6s

If you pay attention to items that drop you will see that links always go the same way :

1 2
3 4
5 6

Left to right then top to bottom.

There are only 2 five links : 1 2 3 4 5 and 2 3 4 5 6

However, with a 6s item, you can also get 4 linking bars in the wrong spots : 1-2-3-4..5-6, 1-2..3-4-5-6 and 1-2-3..4-5-6.

Therefore my guess is that the game rolls links this way : % chance for a link between 1-2, % chance between 2-3, % chance for a link between 3-4, etc. With most likely some diminishing formula if you already rolled a link.

On a 6s item you have 2/5 chances that your 4 linking bars will actually form a 5L. On a 5s item 4 linking bars is necessarily a 5L.

Now it is possible they have a separate formula to roll link probabilities on 4, 5 and 6socket items, but I'd say its quite unlikely.

From my personal experience, its easier to get 5L on a 5s item. But you always want to roll on a 6s item if possible, just in case you're lucky and get 6L.