diff --git a/lib/options/options_pricing_lib.py b/lib/options/options_pricing_lib.py
index ee978c3..8548b4e 100644
--- a/lib/options/options_pricing_lib.py
+++ b/lib/options/options_pricing_lib.py
@@ -387,7 +387,7 @@ def calc_order_size(
     ct_mult: float,
     min_sz: int,
     budget_usdc: float | None = None,
-    budget_buffer: float = 0.95,
+    budget_buffer: float = 1.0,
     eth_amount: float | None = None,
     sheets: int | None = None,
     budget_cap: float | None = None,
diff --git a/lib/options/options_register.py b/lib/options/options_register.py
index 4bb65cb..5419b6a 100644
--- a/lib/options/options_register.py
+++ b/lib/options/options_register.py
@@ -250,9 +250,22 @@ def _compound_full_enabled() -> bool:
 
 
 def _normalize_size_mode(mode: str) -> tuple[str, str | None]:
-    """USDC 预算/全仓模式已下线;统一落到指定张数."""
-    m = (mode or "sheets").strip() or "sheets"
+    """币本位保留打满/复利;USDC 预算模式已下线,落到指定张数."""
+    m = (mode or "").strip()
+    if m == "eth_amount":
+        m = "eth"
+    coin = False
+    try:
+        from lib.options.options_margin_mode_lib import is_coin_margin_mode
+
+        coin = bool(is_coin_margin_mode())
+    except Exception:
+        coin = False
+    if not m:
+        return ("budget_full" if coin else "sheets"), None
     if m in ("compound_full", "budget_full"):
+        if coin:
+            return m, None
         return "sheets", "USDC 期权模式已下线,已改用指定张数"
     return m, None
 
@@ -587,7 +600,7 @@ def register_options_routes(app: Flask, cfg: dict[str, Any]) -> None:
         ask = q.get("ask")
         ct_mult = q.get("ct_mult") or 0.01
         min_sz = q.get("min_sz") or 1
-        mode = (request.args.get("mode") or "sheets").strip()
+        mode = (request.args.get("mode") or "").strip()
         sheet_count = None
         try:
             if request.args.get("sheets"):
@@ -766,7 +779,7 @@ def register_options_routes(app: Flask, cfg: dict[str, Any]) -> None:
             return jsonify({"ok": False, "msg": f"交易模式校验失败: {e}", "can_open": False})
         data = request.get_json(silent=True) or {}
         inst_id = (data.get("inst_id") or "").strip()
-        mode = (data.get("mode") or "sheets").strip()
+        mode = (data.get("mode") or "").strip()
         mode, mode_note = _normalize_size_mode(mode)
         signal_note = (data.get("signal_note") or "").strip()
         # 中控条件单占用时禁止手动开仓