Point taken, but I also found this:
"However, the normal blood pH of 7.4 is outside the optimal buffering range; therefore, the addition of protons to the blood due to strenuous exercise may be too great for the buffer alone to effectively control the pH of the blood. When this happens, other organs must help control the amounts of CO2 and HCO3- in the blood"
Figure 4 on the same page has a titration curve showing that blood ph is outside of the "Maximum buffer range."http://www.chemistry.wustl.edu/~edudev/LabTutorials/Buffer/Buffer.html
They suggest that the pH is maintained thanks to the efforts of other organs, such as the lungs, which jettison CO2.
Anyway, basically what you're telling me is that a carbonic acid buffer can operate above pH 7, right?