Please read this post earlier in this thread. It explains everything.
You need to focus on the RPI not the RPI ranking. The Cajuns' RPI is down since entering the weekend. It is down less than it would be because of the play of Cajun opponents ... and to a lesser degree Cajun opponents' opponents. The ranking is up because so many teams around the Cajuns have fallen further this weekend (many losses). Many RPIs have fallen (some significantly) in the RPI Top 12 this weekend.
You are focusing on what the Cajuns will/should do in the RPI rankings if they sweep ... but you are leaving far too much out of the equation. Just by itself, the Cajuns' RPI (calculated value, not the ranking) falls by sweeping UALR. But there is much more to it.
You also need to consider how tightly packed the teams are. Also, the Cajuns are about as close to #11 as they are #6 (from their #7 spot). They are a mere .0006 ahead of Ole Miss. The result of a single opponent can close that gap. It can turn on a dime when you are this tightly packed. The next question I could be asked tomorrow is why the Cajuns dropped four spots because they won today. It makes sense if you look at the RPI values and pay attention to what the other teams do. The Cajuns could also possibly move up two spots if they win and Florida State and Indiana lose ... along with help from Cajun opponents.
Brian