I think it is way low... Maybe so looking at the results of the 12 hours of Sebring for 2015 the GTD (GT3ish cars) pitted for tires around 69 minutes in, or 33.3 laps at an average of 2:04 per lap using the best times since that pit was under yellow and at the beginning of the race I am assuming they were more like ~29-30 laps in. Also since it was a full course caution I can't comment on how much the tires were needed, it was most likely a strategy call. If we use the 29 laps as a marker they went ~108 miles before pitting for tire or fuel.
Now here is the disclaimer that none of this matters: the Corvette in the demo is running street tires, I don't know in race conditions which would last longer street vs race, I assume race since they will be built to handle the abuse but I haven't personally looked into it. I don't know what size fuel tank is on the GTD Porsches, I'd be willing to bet money it's not 37 gallons at the S3 rate or 58 gallon tank at the Z06 rate.
Personally I think fuel consumption
and/or fuel tank size is off (consumption high/ tank size
modeled low) according to your results
@FordGTGuy tire wear
seems to be low.
There is my kinda geeky post for the month, if you have gotten this far thanks for reading, it's a pain to type this much on an iPhone.