I sync it to MBA, syncs, and when it finishes it stays on 'calculating.' I just disconnect it. Wiped iPad, reinstalled, same behavior. It syncs fine, tho.
I’m not sure why this worries you. I get the same behavior, but I know it’s due to the size of the data chunk it is measuring, which in my case exceeds 200 GBs.
Since iPhone syncs in the same process and doesn't show this behavior, it's reasonable to ask why the iPad doesn't act the same. iPhone storage is 128, iPad is just 64.