Edge Conditions in Razz Showdowns

A good friend of mine and lurker here at my journal is a software developer for a startup online poker site. I have served from time to time as their “poker world expert”, which I've enjoyed immensely. These days, they are all accomplished low limit players themselves and don't need my expertise often, but my friend sent me this question that I think I have an answer for, but am curious what others think.

They are implementing Razz, and like all good programmers, they are making sure that every edge condition is handled. My friend has discovered a case where the otherwise excellent Poker Source hand evaluation library (which folks in the poker world who don't also live in the Software Freedom world know as “twodimes”, a web repackager of that library) does something suspicious. We are trying to decide what the right solution is.

Suspend your disbelief for the moment, and consider two Razz hands that have gotten to showdown heads-up. One hand is the 5 5 6 6 7 7 7. The other hand is the 4 4 8 8 9 9 9. Obviously, there wouldn't be a huge pot between these two unless they were total maniacs, but there's at least the antes, the bring-in, and a limp. Who should be awarded that pot?

Poker Source says that the winner is the latter hand. I disagree, I think the former wins. In Razz, we have all learned the rule “best five low cards, aces play low, straights and flushes do not count against you“. We've also learned that if all players at showdown must make at least one pair (because they paired twice, for example), the lowest pair wins. I would argue that this continues on up through the rankings of poker hands, skipping the straights and flushes. So, if all players in the hand must make at least two pair, they should make the lowest two pair they can. By this logic, sixes-up is a worse hand than eights-up, and therefore sixes-up should win.

I am not sure what case could be made for declaring the latter hand the winner. It can make four different five card poker hands: eights-up, nines-up, nines-full-of-eights and nines-full-of-fours. The other hand can also make four: sixes-up, sevens-up, sevens-full-of-sixes and sevens-full-of-fives. Can anyone therefore speculate why Poker Source would think the latter hand is a winner in Razz? Is it just a bug, or are we missing something?