Gysbreght: about the deltaFdown.
In my satellite model (which happens to differ slightly from the table 4 page 56 (0.5 to 1.5 km)), if I use a 4GHz value for the frequency, I have (at 17:05) a -82.7 BFO from the speed of the sat relative to "Perth" GES (mine is -31.80 115.89). Relative speed: ~6.2m/s.
I have a -71.4 value at 17:27.
To have -71,4 at 17:05, I have to use 3.45GHz for the downlink frequency.
All this with a very simple model and using a spherical Earth.
What is sure, IMHO, is that the aircraft have nothing to do with that [part of] BFO.