If I remember correctly, Home Equity Debit is sort-of optional for the Tracing Rules (by default, it is not part of the Tracing Rules, but you can elect into it). You can treat it as Home Equity Debt (up to $100,000 of loan), or it could be treated as Rental Interest.
I think it is allowed to change to from treating it as Home Equity Debt to Rental Interest. In other words, amending would not be necessary UNLESS the debt was over $100,000. However, the reverse is NOT true. Once you start treating it Rental Interest, you can't change it.
