When altering an existing crafted Osteo Striga, amending any of the perks in the first 4 columns requires you to spend 3 Ascendant Alloys if the weapon already has its Catalyst inserted. Other craftable exotics such as Revision Zero doesn’t have this issue. This makes it impossible to try out different perks without crafting a new Striga each time or spending a ridiculous amount of end-game materials.