Blue Essence Change -> Effect on Champion Mastery 6/7 Upgrading

I haven't seen anywhere a statement on how champion mastery 6/7 upgrades will work in the new system... Will we still need the specific champion shard? I have hoarded 30-plus champ shards because I was getting masteries on them all, but I read that it was mathematically better to disenchant them with respect to blue essence gains: https://www.reddit.com/r/leagueoflegends/comments/6xi6nt/how_to_get_84_more_blue_essence_preseason

Please advise.