[Mobhack]

Whichever unit you use will be the spotter from now on, if you make an adjustment. Swapping spotters has no penalty, unless you go to say a non-observer type from a proper FOO, in which case shifting costs more.

BUT SP allows you to plot with an experienced FOO for faster call of fires, and then later use another unit with better LOS if you want precision. There is no complex "oh mission was being called by Bill, but now its George, was 1.2 should now be 2.4 to arrive" stuff.

Who the original observer was is only valid in fires for determining any larger scatters arising for "has no spotter" (he died, or is retreating / routing)OR Shot falls out of LOS of original spotter "spotter has no LOS", which is the same code, arrived at for slightly different reasons. (GPS arty mitigates that somewhat by reducing out-of LOS/no spotter scattering. )