Bladefall of Trathus cost issues

Other than the already reported cost issue with Bladefall of Trathus consuming 10% es with whispers of infinity Seaglass amulet instead of 5%, when comparing costs between manabond and bladefall of trathus, both being 5% of mana (with bladefall being per second), when supported by lifetap, manabond correctly changes to a cost of 5% life, however bladefall of trathus converts the numerical 5% of mana to life cost, which is inconsistent both with the wording on the gems, and wording on the amulet. Bladefall of Trathus behaves as if it was supported by archmage when converting with lifetap. The cost conversion behaviour should be consistent between the amulet and lifetap, and either the 5% mana cost should be worded like added archmage cost, or should correctly be converted to 5% life cost and not 5% of mana cost converted to life.

Interestingly, when bladefall of trathus is supported by both lifetap and using whispers of infinity Seaglass amulet, the cost is converted to es as % cost once again, ignoring the numerical conversion on lifetap but still applying the cost multiplier.