The original plan is shown below.
With the predicted wind direction (blue arrows) the aiming points (AP) were bombed in the order shown so that smoke from each attack would not obscure the next target.
A change in the predicted wind led to the plan being modified.
The new wind direction meant that the order of attack would have to be altered.
As 5 Group had planned to attack the Experimental Works using their "time & distance" technique, their position in the raid was altered.
The well rehearsed attack on the Experimental works by 5 Group meant that the attack order was reversed with JA691 now bombing last.