This is a current issue myself and other service advisers are dealing with at Honda. The oil consumption issue we're facing (on certain year Accords and CR-Vs) is that the original PCM calibration somehow would cause the oil control rings to clog, allowing excess oil into the cylinders. We've had several come in 2-3 quarts low (in a 4.5 quart system). The repair is to replace the rings and pistons, and reflash the PCM. None of these vehicles blow smoke or have any visible signs.
You may have a similar issue, clogged/broken oil control rings.
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