diff --git a/dump1090.c b/dump1090.c
index 150126c..64087f1 100644
--- a/dump1090.c
+++ b/dump1090.c
@@ -918,7 +918,10 @@ int main(int argc, char **argv) {
                 detectModeS(Modes.magnitude, MODES_ASYNC_BUF_SAMPLES);
 
             // Update the timestamp ready for the next block
-            Modes.timestampBlk += (MODES_ASYNC_BUF_SAMPLES*6);
+            if (Modes.oversample)
+                Modes.timestampBlk += (MODES_ASYNC_BUF_SAMPLES*5);
+            else
+                Modes.timestampBlk += (MODES_ASYNC_BUF_SAMPLES*6);
             Modes.stat_blocks_processed++;
         } else {
             pthread_cond_signal (&Modes.data_cond);
diff --git a/mode_s.c b/mode_s.c
index 80b7765..9c9903f 100644
--- a/mode_s.c
+++ b/mode_s.c
@@ -2292,7 +2292,7 @@ void detectModeS_oversample(uint16_t *m, uint32_t mlen) {
         // be correct, but this can be handled by the next layer.
         if ( (msglen > 0) && (errors      <= MODES_MSG_ENCODER_ERRS) ) {
             // Set initial mm structure details
-            mm.timestampMsg = Modes.timestampBlk + (j*5);
+            mm.timestampMsg = Modes.timestampBlk + (j*5) + initial_phase;
             mm.signalLevel = 0;
             mm.phase_corrected = 0;