CNN reporting 2 airasia bodies found 600 miles away
Without flotation assistance, such as an inflated life vest, a human body immersed in water will sink. It then takes at least 48 hours for the decomposing body to produce enough internal gases for the body to rise to the surface. During this process, as well as afterwards, the body is subject to any local currents.
As the accident occurred on 28 DEC 14 and these two bodies were found on 27 JAN 15, 29 days have passed, which amounts to an average movement of under one knot for the whole period.
"Do the Maths."
Perfectly explicable.