Berry,If it is just the last hole that is questionable, it may be possible to trim that end of the air dam short so it ends at the next hole. Or you could trim both ends if it looks uneven.
My gen 1 air dam is starting to look bad and I would like to remove it completely. The only thing holding me back is the lack of work space under there. I will need some jack stands, I think. It will be nice to not hear scraping any more. I'm not worried about a slight loss of efficiency since there are benefits to losing the air dam.
New member here in my 60's with a used/new to me 2014 Volt I bought week and a ha!f ago. Previous owner beat up the lower air dam. It was pretty unsightly and ragged. I don't know if you're still contemplating removing the lower air dam.
Two nights ago I put a large harbor freight movers pad on the floor and got down on the floor and slowly removed the air dam. It wasn't hard at all. Getting up from the floor was another matter lol. You don't need to jack up or raise the car at all in order to remove the air dam.
I'm still undecided, if I'll replace it with the shorter version.