See The OTC Space’s summary of the latest Q+A from ESMA. The answer added in OTC question 3 about Notional for the clearing threshold has relevance to the commodities area, since you would think that if one can consider a changing notional for amortising swaps, then you would definitely be able to do the same for a commodities trade.

So, this could give the green light to using the undelivered notional (rather than the original notional) for the GNV. All comments are welcome on this.