“These results come with ABSOLUTELY NO WARRANTY”
Their results are consistent with NASA’s 15/300kt/20 degree/20000m/sec scenario, except the over pressure, which was demonstrably greater, about 5X greater.
I don’t think the calculator is including the sonic boom from the passage, just the explosion.
However, an article in Nature states the blast damage was from the explosion, not the sonic boom:
http://www.nature.com/news/russian-meteor-largest-in-a-century-1.12438
On further thought, I suspect that the overpressure was much higher than the calculator because the (simple) calculator may simply have the air blast effects be spherical, when in reality they were focused along the path.
The paper explaining the calculator is quite technical and can be found here:
http://impact.ese.ic.ac.uk/ImpactEffects/effects.pdf