Adwords Ad Sitelinks: How does adwords decide which sitelink to show?

From the 10 sitelinks I added only 4 of them are always showing.

[Hyponeros]

I was taking advantage of the new adwords feature that allow to show 4 additional links in your ad and it is working as expected besides for one point:

I added 10 links in the order of preference but only the 4 first links are always showing even if I add a keyword related to the last link.

Let's say I am selling cakes and my site is 'GoodCakes.com'. I am bidding on the keyword "goodcakes.com" The title of my tenth link is "Chocolate cake". Even if my search query is "goodcakes.com chocolate" only my 4 first links are showing and not my tenth link. I would expect it to show since obviously it is related to the search query.

Did anybody else see only the top 4 links? Even if some search queries are related to one of the other titles? How can I have the other links showing up?

[PayMePerClick]

From what I've seen, and everyone I've spoken to, for the time being the first four will be the only ones shown regardless of any search. There is plenty of room to the right to eventually display all 10 though. I'm not sure if it's a glitch or not because the instructions do say you can add up to 10.

[Hyponeros]

I am not expecting all 10 to show at the same time but the 10 links to rotate. It is said that site links allows to "showcasing additional targeted and relevant links" but it appears on my side that they show only the 4 first links.