Thank you @jtax
However, I found that your last response is mostly repeating what you have already said. As I mentioned in my yesterday's post, lets leave aside the question of the use of US code or international code for Line 2 for now (I follow your points on this, while acknowledging differing opinions of experts regarding which is right).
I was hoping to hear your thoughts on the specific item "depreciation" and, because of how it is not treated in the US like any other expense item, its effect on the FTC calculation based on the concerns I outlined in the example I shared (e.g. expiry of FTCs that were not allowed in earlier years (due to depreciation) before the event leading to depreciation recapture that would effectively allow FTCs but they are now long gone).
