Capt Bloggs is correct
From the AMM
Strobe Lights
The two forward facing strobe lights and the rearward facing strobe light flash at the same time at a rate of 55 +/- 5 flashes per minute. A second flash tube in the forward facing strobe lights flashes at a rate of 55 +/- 5 flashes per minute. This gives 110 +/- 10 flashes per minute in the forward direction and 55 +/- 5 flashes per minute in the rearward direction.
What I said earlier still stands, when they are switched on they are all powered at the same time from the same source. Over time with the tolerance of +/- 10 they will eventually stop flashing together.