The ATK stat for Knight, Warrior, Assassin legendary weapon need to be updated, looks like it does not consider the patch where Vespa buff ATK of knight and warrior weapon. (28 November 2017 patch) But the ATK stat for the UW is already correct.
Seems that the game has added this, and it isn't showing the actual base mana/recovery of the heroes in-game. Would still need to reflect actual game behavior but should put up a note that each hero has a hidden base mana recovery.
Two functions in more or less the same context ItemDetails.vue and getters.js, such can be done by storing the scale values on the store and make a getter to calculate a stat based on current state, doing so does not violate the idea of a single source of truth