diff --git a/backend/tft/sim/player.py b/backend/tft/sim/player.py
index 9f37265..52d97e4 100644
--- a/backend/tft/sim/player.py
+++ b/backend/tft/sim/player.py
@@ -193,7 +193,15 @@ def grab_carousel_unit(p: PlayerState, pool: Pool, rng: random.Random) -> None:
 
 
 def fill_board(p: PlayerState, artifact: dict) -> None:
-    """Wie in TFT: freie Board-Plätze werden beim Kampfstart von der Bank aufgefüllt."""
+    """Freie Board-Plätze auffüllen und stärkere Bank-Units einwechseln."""
     p.bench.sort(key=lambda u: -unit_worth(artifact, u))
     while len(p.board) < p.level and p.bench:
         p.board.append(p.bench.pop(0))
+    for i, u in enumerate(p.board):
+        if not p.bench:
+            break
+        best = max(p.bench, key=lambda b: unit_worth(artifact, b))
+        if unit_worth(artifact, best) > unit_worth(artifact, u):
+            p.bench.remove(best)
+            p.bench.append(u)
+            p.board[i] = best
diff --git a/backend/tft/sim/policy.py b/backend/tft/sim/policy.py
index 8cfebef..e3700eb 100644
--- a/backend/tft/sim/policy.py
+++ b/backend/tft/sim/policy.py
@@ -12,21 +12,25 @@ from tft.sim.player import InvalidAction, PlayerState
 from tft.sim.pool import Pool
 
 ARCHETYPES = {
+    # roll_at_level: ab diesem Level (und Stage >= 4) wird auf roll_floor gerollt.
     "fast8": {
         "level_targets": {"2-1": 4, "2-5": 5, "3-2": 6, "4-1": 7, "4-2": 8, "5-2": 9},
-        "roll_rounds": {"4-2": 30, "5-2": 20},
+        "roll_at_level": 8,
+        "roll_floor": 30,
         "roll_low_hp": 40,
         "slow_roll_level": None,
     },
     "streaker": {
         "level_targets": {"2-1": 4, "2-5": 5, "3-1": 6, "3-5": 7, "4-5": 8, "5-5": 9},
-        "roll_rounds": {"4-1": 30, "4-5": 20},
+        "roll_at_level": 7,
+        "roll_floor": 30,
         "roll_low_hp": 50,
         "slow_roll_level": None,
     },
     "reroll": {
         "level_targets": {"2-1": 4, "2-5": 5, "3-2": 6, "5-1": 7, "6-1": 8},
-        "roll_rounds": {},
+        "roll_at_level": None,
+        "roll_floor": 30,
         "roll_low_hp": 40,
         "slow_roll_level": 6,  # ab Level 6: Gold über 50 verrollen (Slow-Roll)
     },
@@ -69,8 +73,9 @@ def act(p: PlayerState, pool: Pool, artifact: dict, cfg: dict, rng: random.Rando
         floor = 50
     if p.level >= max(params["level_targets"].values()):
         floor = 50  # Endstufe erreicht: Überschuss in Upgrades rollen
-    if label in params["roll_rounds"]:
-        floor = params["roll_rounds"][label]
+    roll_level = params.get("roll_at_level")
+    if roll_level is not None and p.level >= roll_level and rnd["stage"] >= 4:
+        floor = params["roll_floor"]
     if rnd["stage"] >= 4 and p.hp < params["roll_low_hp"]:
         floor = 0  # Not-Rolldown bei niedrigem Leben
 
@@ -102,13 +107,15 @@ def _buy_from_shop(p: PlayerState, pool: Pool, artifact: dict) -> None:
 
 
 def _buy_upgrades(p: PlayerState, pool: Pool, artifact: dict) -> None:
+    """Im Rolldown: Kopien für Upgrades UND neue starke Carries (4-Cost+) kaufen."""
     for slot, api in enumerate(list(p.shop)):
         if api is None:
             continue
         cost = artifact["static"]["units"][api]["cost"]
         owned = sum(1 for u in p.board + p.bench
                     if u["api_name"] == api and u["stars"] < 3)
-        if p.gold >= cost and owned >= 1:
+        wants = owned >= 1 or (cost >= 4 and len(p.bench) < 7)
+        if p.gold >= cost and wants:
             try:
                 player.buy(p, slot, pool, artifact)
             except InvalidAction: