If it's blue smoke only from a standing start, it will most likely be bad valve stem seals - it is the #1 culprit for oil consumption. If it looks like the smoke is mostly cold start and on hard acceleration then it's more likely to be worn rings. Sometimes rings and ring grooves get gummed up with burnt oil which prevents them from sealing as efficiently. The oil flush 'may' break up the gunk on the pistons and restore some compression and reduction in oil use but it's inevitable it needs new rings. You can get away with doing a dirty reco by getting a set of new standard size rings and giving the cylinder bores a once over with a bore honing tool as long as the cylinder bores aren't ripped up. The 2.4 is an easy engine to navigate around and work on.