Will you share those?
You mean this one that says Allomancy draws from an outside source but Feruchemy is powered by the feruchemist?
Or this one that ties Allomancy to AonDor while also saying that Feruchemy stores it's charge in the metal?
Where are you getting that from? I don't recall gems ever cracking by changing the light that is in them.
There is a simple answer, you cannot tap aluminum any identity stored in aluminum is gone forever.
Both terms are interchangeable.