diff --git a/internal/plugin/plugin.go b/internal/plugin/plugin.go
index b6e58df..13c8d05 100644
--- a/internal/plugin/plugin.go
+++ b/internal/plugin/plugin.go
@@ -95,7 +95,7 @@ func NewPREF64(prefix netip.Prefix, maxInterval time.Duration) *PREF64 {
 	// See https://datatracker.ietf.org/doc/html/rfc8781#section-4.1-2
 	lifetime := maxPref64Lifetime
 	if int(maxInterval.Seconds())*3 < int(lifetime.Seconds()) {
-		lifetimeSeconds := int(maxInterval.Seconds())
+		lifetimeSeconds := int(maxInterval.Seconds()) * 3
 		if r := int(lifetimeSeconds) % 8; r > 0 {
 			lifetimeSeconds += 8 - r
 		}
diff --git a/internal/plugin/plugin_test.go b/internal/plugin/plugin_test.go
index 6b6c326..686af79 100644
--- a/internal/plugin/plugin_test.go
+++ b/internal/plugin/plugin_test.go
@@ -856,7 +856,7 @@ func TestNewPREF64(t *testing.T) {
 			want: &PREF64{
 				Inner: &ndp.PREF64{
 					Prefix:   simplePrefix,
-					Lifetime: time.Minute * 10,
+					Lifetime: time.Minute * 30,
 				},
 			},
 		},
@@ -889,7 +889,7 @@ func TestNewPREF64(t *testing.T) {
 			want: &PREF64{
 				Inner: &ndp.PREF64{
 					Prefix:   simplePrefix,
-					Lifetime: time.Second * 16,
+					Lifetime: time.Second * 32,
 				},
 			},
 		},