Additional Service Account (Playstation)

So I couldn't find a clear answer anywhere online and so I figured I'd ask here.

I currently own FFXIV on my PC and I'm thinking of getting it on my playstation as well. When taken to the playstation store page I see an option for an Additional Service Account. If I bought FFXIV for my Square account on my playstation could I pay the $20 for an additional account to say let my wife play through my PSN ID since I would have an additional account? I just don't want to have to Buy FFXIV twice on the playstation to allow her to play with me if she likes it.

All in all I would like to avoid having to buy two additional copies of the game for the playstation since I already own one on PC. If this is the only option I think my wife will just pass on this and I will only play on PC. Seems very money grubby if this is the case.