I noticed that too but I don't think many have seen it. It is actually a pretty good point by Exponent. Both the Colts and Patriots would have had to be using gauges that were off similar to the logo gauge or both would have had to supply balls that were under the requested specs by the same variance. Seems unlikely. Then again, since Walt's recollection is off as to which gauge he used, it could certainly mean that it was off elsewhere as well. And with such a vary low tolerance between passing and not, every little detail counts. Its way too many assumptions to really be a conclusive judgement. This is my biggest problem with the report.
Below is the reasoning in the Exponent appendix in the report. Now why didn't they try to get the Colts and Patriots gauges to shore up this point? This is a big lapse by Exponent/Wells if you ask me. If Pats can show that McNally's gauge reads high then they blow away the Exponent conclusions.
From exponent:
It has been shown that the Logo Gauge consistently reads higher than all other gauges analyzed in this investigation. As a result, it is very unlikely that the Logo Gauge would have read similarly to the gauges used by each team. Therefore, it is most likely that the gauge used by Walt Anderson prior to the game was the Non-Logo Gauge, which read similarly to the Master Gauge and other gauges tested during the investigation.