Tough to do, but I will have a go at it.
In looking at last years schedule, if I did this correctly and my math is right, Iowa ended up with a weighted win percentage of .616 (15.4 wins, 9.6 losses). Say you flip the loss at Nebraska to a win that win percentage jumps to .651 (16.8 wins, 9 losses). That is a difference of .035, divide that number by 4 since it is 25% of the RPI score and you get .00875. Iowa ended up with an RPI score of .551 which was good for 78th (using ESPN), add on the RPI difference (.00875) and you get .55975 RPI which would have moved Iowa up to 64th.
This is not exact since there are other minor adjustments that take place when you convert losses into wins. But it gives you a general idea of the impact the win percentage has on the RPI at the end of the season. Right now Iowa's RPI is jumping all over the place on a day to day basis that is because every win or loss a previous opponent gets moves the RPI score more now than it does at the end of the season. At the end of the season the opponents wins or losses do not have much of an impact because the numbers are so large while Iowa's wins or losses moves it more since you are still moving a relatively small number.
Nerd!