isSkillXPInRange

Whether a kill is close enough to the player's level to award skill XP.

Under scaled combat this check is skipped entirely, and that is deliberate. Scaled combat normalizes the mob to the player, so the fight is the same difficulty at every mob level and "this mob is too far beneath you" is meaningless by construction. Worse, the reward level passed in under scaled combat is the player's COMBAT level - an average across three skills - while skillLevel is a single skill. Comparing those two different scales permanently locked out specialists: an axes-35 / swords-10 / armor-15 player has combat level 20 and needs 30, so the gate blocked precisely the skill that was ahead and the gap could never close. Excessive farming under scaled combat is handled by the kill-count cap instead.