First of all, its up to the PSO (pro shop operator) to make the customers happy. He/she should give suggestions and personal opinion, but ultimately the decision is up to you. So, if you requested a specific layout and didn't get it, then that ball should be replaced. Otherwise, you are going to have a fully plugged and redrilled ball before you even get to throw it. Missing the span, on the other hand, is an honest mistake...especially if both balls are off by the same amount (if they are both different... then that's just sloppy work and you should look else where). Generally a small amount can be easily fixed by either plugging and moving the thumb a little or installing a thumb slug. If the spans are off from the ball you provided, then its up to the proshop to correct their error, free of charge...
S^2
--------------------
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
-Strapper Squared