Connecting BIAS to TC+ won't make a big difference in accuracy as long as it is within the part's voltage ratings.
If TC- is connected to BIAS, then TC+ will be at VBIAS + Vdifference. If TC+ is connected to BIAS, then TC- will be at VBIAS - Vdifference.
The voltage of TC+ and TC- will be shifted around depending on which input you bias, but the voltage difference will remain the same.