High Alching Anomaly?

when i'm at the addy stage, i notice that squares give more money than shorts so i simply assumed that this is also true for runites. but it ain't.


rune short sword - 1 bar - gives 12480

rune square shield - 2 bars - gives 23040 (11520 per bar)


so i stand to lose 960 gp per rune bar even if i save on nats. i do feel that the better item should alch for more gp.