diff --git a/tsdb/chunkenc/benchmark_test.go b/tsdb/chunkenc/benchmark_test.go
index bf72f855ef..1679158f16 100644
--- a/tsdb/chunkenc/benchmark_test.go
+++ b/tsdb/chunkenc/benchmark_test.go
@@ -80,7 +80,7 @@ func foreachFmtSampleCase(b *testing.B, fn func(b *testing.B, f fmtCase, s sampl
 		{
 			// Delta simulates delta type or worst case for cumulatives, where ST
 			// is changing on every sample.
-			name: "vt=constant/st=delta",
+			name: "vt=constant/st=delta-exclusive",
 			samples: func() (ret []triple) {
 				t, v := initT, initV
 				for range nSamples {
@@ -91,6 +91,20 @@ func foreachFmtSampleCase(b *testing.B, fn func(b *testing.B, f fmtCase, s sampl
 				return ret
 			}(),
 		},
+		{
+			// Delta simulates delta type or worst case for cumulatives, where ST
+			// is changing on every sample.
+			name: "vt=constant/st=delta-inclusive",
+			samples: func() (ret []triple) {
+				t, v := initT, initV
+				for range nSamples {
+					st := t // ST is the same as the previous t.
+					t += 15000
+					ret = append(ret, triple{st: st, t: t, v: v})
+				}
+				return ret
+			}(),
+		},
 		{
 			name: "vt=random steps/st=0",
 			samples: func() (ret []triple) {
@@ -198,7 +212,7 @@ func foreachFmtSampleCase(b *testing.B, fn func(b *testing.B, f fmtCase, s sampl
 			}(),
 		},
 		{
-			name: "vt=random 0-1/st=delta",
+			name: "vt=random 0-1/st=delta-exclusive",
 			samples: func() (ret []triple) {
 				t, v := initT, initV
 				for range nSamples {
@@ -210,6 +224,19 @@ func foreachFmtSampleCase(b *testing.B, fn func(b *testing.B, f fmtCase, s sampl
 				return ret
 			}(),
 		},
+		{
+			name: "vt=random 0-1/st=delta-inclusive",
+			samples: func() (ret []triple) {
+				t, v := initT, initV
+				for range nSamples {
+					st := t                              // ST is the same as the previous t.
+					t += int64(r.Intn(100) - 50 + 15000) // 15 seconds +- up to 100ms of jitter.
+					v += r.Float64()                     // Random between 0 and 1.0.
+					ret = append(ret, triple{st: st, t: t, v: v})
+				}
+				return ret
+			}(),
+		},
 	}
 
 	for _, f := range []fmtCase{