diff --git a/dive.c b/dive.c
index 950948b59..c07912ebd 100644
--- a/dive.c
+++ b/dive.c
@@ -678,7 +678,8 @@ static void fixup_dive_dc(struct dive *dive, struct divecomputer *dc)
 		if (asc_desc_time * 2 >= duration)
 			asc_desc_time = duration/2;
 
-		dc->meandepth.mm = depth*(duration-asc_desc_time)/duration;
+		if (!dc->meandepth.mm)
+			dc->meandepth.mm = depth*(duration-asc_desc_time)/duration;
 		if (depth > maxdepth)
 			maxdepth = depth;
 	} else {
diff --git a/dives/sac-test.xml b/dives/sac-test.xml
index 14ee3f17b..fe0f51994 100644
--- a/dives/sac-test.xml
+++ b/dives/sac-test.xml
@@ -6,7 +6,7 @@
   <location>SAC test dive 1</location>
   <notes>SAC should be 20l/min (0.7063 cuft/min)
 We have exactly 100 ATM of gas in a 10l cylinder, average 10m for 25min</notes>
-  <cylinder size='10 l' description='10l' start='202.6 bar' end='101.3 bar' />
+  <cylinder size='10.0 l' description='10l' start='202.6 bar' end='101.3 bar' />
   <divecomputer>
   <depth max='10.0 m' mean='10.0 m' />
   <sample time='0:00 min' depth='10.0 m' />
@@ -21,7 +21,7 @@ We have exactly 100 ATM of gas in a 10l cylinder, average 10m for 25min</notes>
   <location>SAC test dive 2</location>
   <notes>SAC should be 20l/min (0.7063 cuft/min)
 We have exactly 100 ATM of gas in a 10l cylinder, average 10m for 25min</notes>
-  <cylinder size='10 l' description='10l' start='202.6 bar' end='101.3 bar' />
+  <cylinder size='10.0 l' description='10l' start='202.6 bar' end='101.3 bar' />
   <divecomputer>
   <depth max='20.0 m' mean='10.0 m' />
   <sample time='0:00 min' depth='0.0 m' />
@@ -33,11 +33,11 @@ We have exactly 100 ATM of gas in a 10l cylinder, average 10m for 25min</notes>
   <location>SAC test dive 3</location>
   <notes>SAC should be 20l/min (0.7063 cuft/min)
 We have exactly 100 ATM of gas in 15l of cylinder, average 20m for 25min</notes>
-  <cylinder size='10 l' description='10l' start='202.6 bar' end='101.3 bar' />
-  <cylinder size='5 l' description='10l' start='202.6 bar' end='101.3 bar' />
+  <cylinder size='10.0 l' description='10l' start='202.6 bar' end='101.3 bar' />
+  <cylinder size='5.0 l' description='10l' start='202.6 bar' end='101.3 bar' />
   <divecomputer>
+  <depth max='40.0 m' mean='20.0 m' />
   <event time='17:00 min' name='gaschange' />
-  <depth max='20.0 m' mean='10.0 m' />
   <sample time='0:00 min' depth='0.0 m' />
   <sample time='5:00 min' depth='20.0 m' />
   <sample time='10:00 min' depth='40.0 m' />
@@ -46,16 +46,16 @@ We have exactly 100 ATM of gas in 15l of cylinder, average 20m for 25min</notes>
   <sample time='25:00 min' depth='0.0 m' />
   </divecomputer>
 </dive>
-<dive number='4' date='2013-02-24' time='12:26:04' duration='25:00 min'>
-  <location>SAC test dive 3</location>
+<dive number='4' date='2013-02-24' time='12:26:04' duration='30:00 min'>
+  <location>SAC test dive 4</location>
   <notes>SAC should be 20l/min (0.7063 cuft/min)
 This adds a 5-minute surface time to the middle of the dive.
 We have exactly 100 ATM of gas in 15l of cylinder, average 20m for 25min</notes>
-  <cylinder size='10 l' description='10l' start='202.6 bar' end='101.3 bar' />
-  <cylinder size='5 l' description='10l' start='202.6 bar' end='101.3 bar' />
+  <cylinder size='10.0 l' description='10l' start='202.6 bar' end='101.3 bar' />
+  <cylinder size='5.0 l' description='10l' start='202.6 bar' end='101.3 bar' />
   <divecomputer>
+  <depth max='40.0 m' mean='16.666 m' />
   <event time='22:00 min' name='gaschange' />
-  <depth max='20.0 m' mean='10.0 m' />
   <sample time='0:00 min' depth='0.0 m' />
   <sample time='5:00 min' depth='20.0 m' />
   <sample time='10:00 min' depth='40.0 m' />
@@ -65,5 +65,15 @@ We have exactly 100 ATM of gas in 15l of cylinder, average 20m for 25min</notes>
   <sample time='30:00 min' depth='0.0 m' />
   </divecomputer>
 </dive>
+<dive number='5' date='2013-02-24' time='13:26:04' duration='25:00 min'>
+  <location>SAC test dive 5</location>
+  <notes>SAC should be 20l/min (0.7063 cuft/min)
+This verifies that it works without any sample data too.
+We have exactly 100 ATM of gas in 15l of cylinder, average 20m for 25min</notes>
+  <cylinder size='10.0 l' description='10l' start='202.6 bar' end='101.3 bar' />
+  <divecomputer>
+  <depth max='13.5 m' mean='10.0 m' />
+  </divecomputer>
+</dive>
 </dives>
 </divelog>