diff --git a/tests/Server/ZB.MOM.WW.OtOpcUa.Host.Tests/Configuration/HistorianBackendRegistryTests.cs b/tests/Server/ZB.MOM.WW.OtOpcUa.Host.Tests/Configuration/HistorianBackendRegistryTests.cs
index b276067b..21f9eb95 100644
--- a/tests/Server/ZB.MOM.WW.OtOpcUa.Host.Tests/Configuration/HistorianBackendRegistryTests.cs
+++ b/tests/Server/ZB.MOM.WW.OtOpcUa.Host.Tests/Configuration/HistorianBackendRegistryTests.cs
@@ -149,15 +149,24 @@ public sealed class HistorianBackendRegistryTests
         IHistorianDataSource Source(ServerHistorianOptions o, IConfiguration c) =>
             HistorianBackendRegistry.Resolve(o, c).CreateDataSource(sp);
 
-        // #681: the ten per-sample aggregates (raw-evaluated) + the two AVEVA-native ones.
-        Source(Gateway(), Cfg).SupportedAggregates.ShouldBe(
-            [
-                HistoryAggregateType.Average, HistoryAggregateType.Count, HistoryAggregateType.Minimum,
-                HistoryAggregateType.Maximum, HistoryAggregateType.Range, HistoryAggregateType.Start, HistoryAggregateType.End,
-                HistoryAggregateType.Delta, HistoryAggregateType.MinimumActualTime, HistoryAggregateType.MaximumActualTime,
-                HistoryAggregateType.TimeAverage, HistoryAggregateType.Total,
-            ],
-            ignoreOrder: true);
+        // #681: the ten per-sample aggregates (raw-evaluated). The two AVEVA-native ones (TimeAverage / Total) are
+        // refused and not advertised by default until historiangw#27 is fixed (#746, R08:2.1) ...
+        HistoryAggregateType[] gatewayRawEvaluated =
+        [
+            HistoryAggregateType.Average, HistoryAggregateType.Count, HistoryAggregateType.Minimum,
+            HistoryAggregateType.Maximum, HistoryAggregateType.Range, HistoryAggregateType.Start, HistoryAggregateType.End,
+            HistoryAggregateType.Delta, HistoryAggregateType.MinimumActualTime, HistoryAggregateType.MaximumActualTime,
+        ];
+        Source(Gateway(), Cfg).SupportedAggregates.ShouldBe(gatewayRawEvaluated, ignoreOrder: true);
+
+        // ... and served again, through the Host's resolve path, once ServerHistorian:Gateway:EnableNativeTimeWeighted is on.
+        var nativeOn = new ServerHistorianOptions
+        {
+            Backend = "Gateway", Enabled = true, Endpoint = "http://localhost:5222", ApiKey = "histgw_id_secret", UseTls = false,
+            Gateway = new GatewayHistorianSettings { EnableNativeTimeWeighted = true },
+        };
+        Source(nativeOn, Cfg).SupportedAggregates.ShouldBe(
+            [.. gatewayRawEvaluated, HistoryAggregateType.TimeAverage, HistoryAggregateType.Total], ignoreOrder: true);
         Source(new ServerHistorianOptions { Backend = "SqlServer", Enabled = true }, SqlCfg())
             .SupportedAggregates.ShouldBe(SqlServed, ignoreOrder: true);
         Source(new ServerHistorianOptions { Backend = "QuestDb", Enabled = true }, QuestDbCfg())