The problem with A/R and elephants is, as has been previously stated, a percentage of casualties are sperad amonst the whole army.

10% losses means you have lost 10% of your precious ele's.

NEVER AUTO RESOLVE WITH ELEPHANTS!!!! This is particularly important if the are Merc elphants or you have no ability to replenish your unit.

(Mind you I feel the same way about my beloved Cretan Archers - I never AR with them!)