I may be missing something obvious, but wouldn't the existence of more than one debris field indicate a midair breakup into a number of large pieces, with the pieces following their own trajectories to the surface and disintegrating further on the way down and/or on impact?
Reasonable question.
However, AF447 definitely hit the ocean in one piece, and there was a spread of
floating debris of up to 3 miles before the first bits were located, a day after it disappeared.
Very buoyant debris that stays mostly on or sticking above the water surface may "sail" with the winds in one direction, whereas debris that is just barely awash may move only with the water currents. Or a combination of the two, diverging with every hour on the surface. Things may break loose underwater after the impact, and float to the surface through varying currents, surfacing some distance from "ground zero."
Or - the aircraft may have broken up only in the last moments, when its dive exceeded structural limits, long (relatively) after whatever "event" occurred at 35000 feet. 5000-10000 feet can be high enough to scatter debris.
So it does not automatically imply the breakup (if any) was the original event.