[Juha]

The rockets were too inaccurate for it to be worth aiming at a specific spot, the probability of a hit was really low. According to Price, the probability of getting at least one hit with a salvo of eight rockets was 0.7%. The British tested air-to-ground rocket fire against a Panther standing alone in an open field, and indeed, the probability of a hit was very low. Was it as low as Price says, maybe not. I tried to dig up the above report, but I coudn't find it on my hard drive. But as I recall, at least a flight's worth of Typhoons were needed in order to have a reasonable probability of hitting a tank. According to Price, on August 7, 1944, the Typhoons used 2088 rockets and 80 tons of bombs in 458 sorties, of which 294 were in the Mortain area, where 7 tanks were disabled/destroyed with rockets and 2 with bombs.
It must also be remembered that sometime around 1942, the British started teaching anti-tank gunners to aim at the tank's center of mass and no longer at a specific point. So it was considered better for the aimers of stationary cannons to aim at the center of the target. In the end, the tank is quite a small target. Tiikeri I size was 6.32 x 3.56 x 3.00 metres.
Similarly, the idea that all planes attacked from the same direction is not very reasonable. A mobility kill would require a hit to the roadwheels or tracks and they were identical on both sides of a tank. Of course, also a rocket hit to the engine compartment cover will stop if not destroy the tank, no matter if it was attacked from the side or behind.
The instructor may well have given the advices as the veteran remembers, but those instructions did not make much sense.