diff --git a/backend/internal/service/admin_service.go b/backend/internal/service/admin_service.go
index 8992e2505d..5d96db45f2 100644
--- a/backend/internal/service/admin_service.go
+++ b/backend/internal/service/admin_service.go
@@ -84,7 +84,6 @@ type AdminService interface {
 	DeleteRedeemCode(ctx context.Context, id int64) error
 	BatchDeleteRedeemCodes(ctx context.Context, ids []int64) (int64, error)
 	ExpireRedeemCode(ctx context.Context, id int64) (*RedeemCode, error)
-	ResetAccountQuota(ctx context.Context, id int64) error
 }
 
 // CreateUserInput represents input for creating a new user via admin operations.
@@ -138,10 +137,9 @@ type CreateGroupInput struct {
 	// 无效请求兜底分组 ID（仅 anthropic 平台使用）
 	FallbackGroupIDOnInvalidRequest *int64
 	// 模型路由配置（仅 anthropic 平台使用）
-	ModelRouting             map[string][]int64
-	ModelRoutingEnabled      bool // 是否启用模型路由
-	MCPXMLInject             *bool
-	SimulateClaudeMaxEnabled *bool
+	ModelRouting        map[string][]int64
+	ModelRoutingEnabled bool // 是否启用模型路由
+	MCPXMLInject        *bool
 	// 支持的模型系列（仅 antigravity 平台使用）
 	SupportedModelScopes []string
 	// Sora 存储配额
@@ -175,10 +173,9 @@ type UpdateGroupInput struct {
 	// 无效请求兜底分组 ID（仅 anthropic 平台使用）
 	FallbackGroupIDOnInvalidRequest *int64
 	// 模型路由配置（仅 anthropic 平台使用）
-	ModelRouting             map[string][]int64
-	ModelRoutingEnabled      *bool // 是否启用模型路由
-	MCPXMLInject             *bool
-	SimulateClaudeMaxEnabled *bool
+	ModelRouting        map[string][]int64
+	ModelRoutingEnabled *bool // 是否启用模型路由
+	MCPXMLInject        *bool
 	// 支持的模型系列（仅 antigravity 平台使用）
 	SupportedModelScopes *[]string
 	// Sora 存储配额
@@ -359,10 +356,6 @@ type ProxyExitInfoProber interface {
 	ProbeProxy(ctx context.Context, proxyURL string) (*ProxyExitInfo, int64, error)
 }
 
-type groupExistenceBatchReader interface {
-	ExistsByIDs(ctx context.Context, ids []int64) (map[int64]bool, error)
-}
-
 type proxyQualityTarget struct {
 	Target          string
 	URL             string
@@ -438,6 +431,10 @@ type userGroupRateBatchReader interface {
 	GetByUserIDs(ctx context.Context, userIDs []int64) (map[int64]map[int64]float64, error)
 }
 
+type groupExistenceBatchReader interface {
+	ExistsByIDs(ctx context.Context, ids []int64) (map[int64]bool, error)
+}
+
 // NewAdminService creates a new AdminService
 func NewAdminService(
 	userRepo UserRepository,
@@ -853,13 +850,6 @@ func (s *adminServiceImpl) CreateGroup(ctx context.Context, input *CreateGroupIn
 	if input.MCPXMLInject != nil {
 		mcpXMLInject = *input.MCPXMLInject
 	}
-	simulateClaudeMaxEnabled := false
-	if input.SimulateClaudeMaxEnabled != nil {
-		if platform != PlatformAnthropic && *input.SimulateClaudeMaxEnabled {
-			return nil, fmt.Errorf("simulate_claude_max_enabled only supported for anthropic groups")
-		}
-		simulateClaudeMaxEnabled = *input.SimulateClaudeMaxEnabled
-	}
 
 	// 如果指定了复制账号的源分组，先获取账号 ID 列表
 	var accountIDsToCopy []int64
@@ -916,7 +906,6 @@ func (s *adminServiceImpl) CreateGroup(ctx context.Context, input *CreateGroupIn
 		FallbackGroupIDOnInvalidRequest: fallbackOnInvalidRequest,
 		ModelRouting:                    input.ModelRouting,
 		MCPXMLInject:                    mcpXMLInject,
-		SimulateClaudeMaxEnabled:        simulateClaudeMaxEnabled,
 		SupportedModelScopes:            input.SupportedModelScopes,
 		SoraStorageQuotaBytes:           input.SoraStorageQuotaBytes,
 	}
@@ -1126,15 +1115,6 @@ func (s *adminServiceImpl) UpdateGroup(ctx context.Context, id int64, input *Upd
 	if input.MCPXMLInject != nil {
 		group.MCPXMLInject = *input.MCPXMLInject
 	}
-	if input.SimulateClaudeMaxEnabled != nil {
-		if group.Platform != PlatformAnthropic && *input.SimulateClaudeMaxEnabled {
-			return nil, fmt.Errorf("simulate_claude_max_enabled only supported for anthropic groups")
-		}
-		group.SimulateClaudeMaxEnabled = *input.SimulateClaudeMaxEnabled
-	}
-	if group.Platform != PlatformAnthropic {
-		group.SimulateClaudeMaxEnabled = false
-	}
 
 	// 支持的模型系列（仅 antigravity 平台使用）
 	if input.SupportedModelScopes != nil {
@@ -1487,10 +1467,6 @@ func (s *adminServiceImpl) UpdateAccount(ctx context.Context, id int64, input *U
 		account.Credentials = input.Credentials
 	}
 	if len(input.Extra) > 0 {
-		// 保留 quota_used，防止编辑账号时意外重置配额用量
-		if oldQuotaUsed, ok := account.Extra["quota_used"]; ok {
-			input.Extra["quota_used"] = oldQuotaUsed
-		}
 		account.Extra = input.Extra
 	}
 	if input.ProxyID != nil {
@@ -1659,7 +1635,13 @@ func (s *adminServiceImpl) BulkUpdateAccounts(ctx context.Context, input *BulkUp
 		repoUpdates.RateMultiplier = input.RateMultiplier
 	}
 	if input.LoadFactor != nil {
-		repoUpdates.LoadFactor = input.LoadFactor
+		if *input.LoadFactor <= 0 {
+			repoUpdates.LoadFactor = nil // 0 或负数表示清除
+		} else if *input.LoadFactor > 10000 {
+			return nil, errors.New("load_factor must be <= 10000")
+		} else {
+			repoUpdates.LoadFactor = input.LoadFactor
+		}
 	}
 	if input.Status != "" {
 		repoUpdates.Status = &input.Status
@@ -2484,7 +2466,3 @@ func (e *MixedChannelError) Error() string {
 	return fmt.Sprintf("mixed_channel_warning: Group '%s' contains both %s and %s accounts. Using mixed channels in the same context may cause thinking block signature validation issues, which will fallback to non-thinking mode for historical messages.",
 		e.GroupName, e.CurrentPlatform, e.OtherPlatform)
 }
-
-func (s *adminServiceImpl) ResetAccountQuota(ctx context.Context, id int64) error {
-	return s.accountRepo.ResetQuotaUsed(ctx, id)
-}
diff --git a/backend/internal/service/ops_concurrency.go b/backend/internal/service/ops_concurrency.go
index c03108c4b9..a571dd4df4 100644
--- a/backend/internal/service/ops_concurrency.go
+++ b/backend/internal/service/ops_concurrency.go
@@ -64,9 +64,12 @@ func (s *OpsService) getAccountsLoadMapBestEffort(ctx context.Context, accounts
 		if acc.ID <= 0 {
 			continue
 		}
-		lf := acc.EffectiveLoadFactor()
-		if prev, ok := unique[acc.ID]; !ok || lf > prev {
-			unique[acc.ID] = lf
+		c := acc.Concurrency
+		if c <= 0 {
+			c = 1
+		}
+		if prev, ok := unique[acc.ID]; !ok || c > prev {
+			unique[acc.ID] = c
 		}
 	}
 
diff --git a/backend/internal/service/ops_metrics_collector.go b/backend/internal/service/ops_metrics_collector.go
index 6c33707138..f93481e7ff 100644
--- a/backend/internal/service/ops_metrics_collector.go
+++ b/backend/internal/service/ops_metrics_collector.go
@@ -391,7 +391,7 @@ func (c *OpsMetricsCollector) collectConcurrencyQueueDepth(parentCtx context.Con
 		}
 		batch = append(batch, AccountWithConcurrency{
 			ID:             acc.ID,
-			MaxConcurrency: acc.EffectiveLoadFactor(),
+			MaxConcurrency: acc.Concurrency,
 		})
 	}
 	if len(batch) == 0 {