Power Estimator Discrepancy

I have run Powerplay to get the 'Total Thermal Power Dissipation" figure for my chip. It says about 8.9 W.

However, I then looked in the same tool at the "Current drawn from Voltage supplies". I placed the figures in a spreadsheet which showed a power consumption of nearly 10 W.

Am I interpreting this correctly? If so there seems to be a large discrepancy.

Any advice helps.