gogreen,
You had too little left over from the original installation?
I've done this when I've been too cheap to buy that extra box, and have had one or two pieces left by the time I'm done.
Typically when I sell a job, I mention to the HO that it's good to have extra flooring when the job is done, just in case something happens down the road. Especially when it's a wood floor.
Of course, hindsight is 20/20, and it's easy for me to tell you this from the comfort of my reclining desk chair.
Hopefully it turns out well.