I'm trying to get approval to save average score per round, per character, on the website. Still, even if that's not done, it's possible to use the score gained from the previous round(player offset).
(multiplayer_is_server),
(agent_get_player_id, ":player_no", ":agent_no"),
(player_get_slot, ":score_offset", ":player_no", slot_player_crpg_player_score_offset),
With score_offset being the the ratio of player's score gained:average score gained * 100. So a player with an offset of 100 will have gained the same as what the average was, for that round. It's also possible to have a negative offset, this will happen only if your total score for the map is negative, though, as offset looks at both previous round score and total map score. +/- 30% reliability doesn't seem that great, tbh.
Alternatively, you can use either of these as well.
(player_get_slot, ":personal_score", ":cur_player", slot_player_crpg_player_score_round), #previous round score
(player_get_slot, ":personal_score_total", ":cur_player", slot_player_crpg_player_score_total), #map score