[thrownaway2424]

Not really. A busy network has a million little buffers and things where your packet might get dropped but succeed 1ms later.

[wtallis]

But those buffers are also often huge and your packet could still come out the other end of one of them 20ms (or 2s, if it's a cable or DSL modem) later. You still want to treat it as evidence of congestion, though.