TMRCA differences?

[sdwfrost]

I'm trying to infer the TMRCA from the sample of trees in the repository. However, I get some slight differences in my estimates of TMRCA compared to the paper. My gist is here, which shows that the TMRCA I calculate is shifted back a bit, although the paper doesn't make any exact claims (just says October 2013 - February 2014). Is this just some rounding error?

[rambaut]

The runs on the repo were run since the BioRxiv version of the paper were posted (as a revision for the peer-reviewed manuscript). So there will be some stochastic differences.