What ROM? Did you assign your own DiSEqC 1.2 positions or allow the receiver to automatically assign the DiSEqC 1,2 motor position number? Sounds like you allowed the STB to set the DiSEqC 1.2 position rather than assigning a custom position?
In the automatic DiSEqC 1.2 assignment, mode, most receivers assign the position number according to the satellite position in the satellite list. If you delete or add a satellite, the DiSEqC motor assignment changes. If a custom DiSEqC 1.2 motor position is assigned, this is retained if the satellite list is modified.
Like you, I would expect that the full satellite list would still be available unless I physically delete the satellite.
ROM 2.0.61. I let it manually assign positions. (I was a little surprised that the position numbers run contrary to the longitude of the satellites, too!)
It's good to know that if I assign a custom number, it'll stay, but this whole business of only dumping the selected satellites smacks of a serious disconnect between the programmer and the user. (Or maybe I'm just weird -- but you know what? I'm the one paying big money for the box, it should do what I want it to do!)