Pip and SKoW demonstrate differences between male and female sexuality.
In Pretty in Pink, Molly pairs up with someone of higher social status and value. In SKoW, Amanda does not with a guy of equal or more accurately lower value, she pairs up, first with Jenns then breaks up, but ostensibly is in the market for same.
Similarly, Keith initially seeks Amanda, but eventually winds up with Watts.
I think the comparisons demonstrate that women are hypergamous. They pair up, not down. This is one reason why the original ending of Pretty in Pink is not tenable.