Board Thread:LOC General Discussion/@comment-216.125.251.254-20130204164334/@comment-5896096-20130206083807

Yes, you have to know that you will only take 10 cards max. So whe your UR EX will be at skill lvl 6-7, using 10 Rare EX won't be enough (probably something like 60% chance). So you need to lvl up the skill of your rare EXs ^^  Usually, I don't use that many rares. I always try to get rare EX (not rare), and I lvl up their skill to 3-4 with commons cards (it's easier when yuo have an energy account during Raid event and Odyssee because you can earn so much skill commons).

Anyway, if you want to succeed and not use rare for nothing = aim for 80% chance. If it still doesn't work = unlucky.. But it happenned to me yesterday (I had 78% something like that !)