Mud for the water....
Mercedes' top five speeds at the speed trap were set on day 1, all on hard tires:
Lap time | Speed | Stint length
2:06 322 10 (lap 3)
1:38 321 6 (lap 3)
1:34 320 9 (lap 2)
1:33 320 10 (lap 4)
1:35 319 10 (lap 3)
On Hamilton's 2nd stint of the day, the first flying lap produced 320kph. Flying laps 1, 2, and 5 are linear with lap time. On laps 3, 6, & 7 he must have deliberately altered his speed or encountered traffic or a multitude of others (DRS use, battery charge, etc.)
1 01:34.875 320
2 01:36.129 307
3 01:36.358 295 (outlier)
4 01:36.829 ---
5 01:36.875 301
6 01:40.932 296 (outlier)
7 01:37.503 308 (outlier)
At the end of the day, I believe this confirms that Mercedes are working to their typical testing strategy of masking their performance as much as possible and also concentrating on higher downforce setups.