Hi OP,
I was reading this thread before our first cruise as we had a similar situation. Back now, and will share our experience for anyone else that cares to wade through the rude comments for an actual answer 🙂
We were traveling with our teenage daughter who is a picky eater and we were undecidied if we should buy her a 2-meal specialty dining package as we wanted her to join us for dinner (we had two credits as part of our FAS package). Well, we chose not to and she just ordered a-la-carte. In both cases, unprompted, the servers put most of our daughters charges on our own 'bill' and it was much cheaper than if we had bought the 2-meal voucher. We got charged the main entree on one occasion and nothing on the second.That would be my recommendation unless you are bringing along a very heavy eater. The meals are quite large. Then use some or all of your savings on an additional tip for the server.