Search areas for the actual crash site
At 420 knots the plane is going 7 miles a minute.
At 0210 we have a position. Presuming the plane was still aimed "roughly" along the planned flightpath and presuming perhaps some pushes by storm winds where could the plane have gotten to by 0214 plus maybe a little Kentucky Windage for surviving a bit past 0214?
"Where could the plane possibly be?" might be a better search criterion than "where do the currents extrapolate backwards to at the time of the crash?"
And, of course, I am fastened on to the apparent fact that the plane was either deceased or was no longer even approximately horizontal after 0214.
Aiming of the satellite antenna is somewhere between a TV yagi on a rotator and a pair of rabbit ears in a high signal area for reference. You can be a whole lot off and it still works. Plus or minus maybe 60 degrees of vertical for a 3dB (half power) loss. Within about 35 degrees you'd have trouble picking the optimum direction without automation.
This is why "what is the region it could have reached in 5 minutes or less is my search criterion. Then match that with the currents to try to refine it all. And I have an untutored hunch that turning an A330 or anything else at FL350 is not "sharp" by any stretch of the imagination unless you are purposely entering a dive as for a bombing run.
JD-EE