Don't really care if you want to fix the bugs in your code (lost enough time already...), but in case you want to fix the conflicting code...No, it is working for me. I did the exact same setup and got 1.26x, and then it went up to 1.38x due to 4 hidden achievements.
You started by telling me the whole system is bad, and then you modified the game code, and then now you are getting some unexpected values, and now you are telling me things are reverted, but I have no way to verify the state of your game, so I'm not going to spend anymore time investigating this unless more people report it.
original code
Code:
(set: _a to 5.5772, _b to -1.4407, _c to -8.9769)
(set: _score_multiplier_temp to _a + _b * (log: $total_stats - _c))
(set: $score_multiplier to (round: (100 * _score_multiplier_temp)) / 100)
(if:$club_timer > 0)[(set:$score_multiplier to $score_multiplier + 0.25)]
(if:$potion_shop_max_action_point_purchased is "true")[(set:$score_multiplier to $score_multiplier - 0.05)]
(if:(a:"cherry pop","swirlin surprise") contains $current_zipple)[(set:$score_multiplier to $score_multiplier + 0.25)]
(if:(is_fem:) and not ($handbag is 0))[(set:$score_multiplier to $score_multiplier + ($handbag_xp_bonus / 100))]
(if: (pill:"Resistance") and (checkdm:$resistance_effect,"side effects","contains","xp penalty"))[
(set: _xp_penalty_count to (count: $resistance_effect's "side effects", "xp penalty"))
(set: $score_multiplier to (max:0,$score_multiplier - (_xp_penalty_count * 0.15)))
]
(set: _level_cap_adjustment to $stats_unobtainable * 0.03)
(set: $score_multiplier to (round: (100 * $score_multiplier * (1 + _level_cap_adjustment))) / 100)
Code:
(set: _a to 5.5772, _b to -1.4407, _c to -8.9769)
(set: _score_multiplier_temp to _a + _b * (log: $total_stats - _c))
(set: _level_cap_adjustment to $stats_unobtainable * 0.03)
(set: $score_multiplier to (round: (100 * _score_multiplier_temp * (1 + _level_cap_adjustment))) / 100)
(if:$club_timer > 0)[(set:$score_multiplier to $score_multiplier + 0.25)]
(if:$potion_shop_max_action_point_purchased is "true")[(set:$score_multiplier to $score_multiplier - 0.05)]
(if:(a:"cherry pop","swirlin surprise") contains $current_zipple)[(set:$score_multiplier to $score_multiplier + 0.25)]
(if:(is_fem:) and not ($handbag is 0))[(set:$score_multiplier to $score_multiplier + ($handbag_xp_bonus / 100))]
(if: (pill:"Resistance") and (checkdm:$resistance_effect,"side effects","contains","xp penalty"))[
(set: _xp_penalty_count to (count: $resistance_effect's "side effects", "xp penalty"))
(set: $score_multiplier to (max:0,$score_multiplier - (_xp_penalty_count * 0.15)))
]