There are a couple of other scenarios.

One being that ALL the samples didn't get into the lab before Christmas so are being run now. Unless a company pays for priority processing the results typically get run on the basis FIFO. If they get shipped by courier its easy to have a big batch from someone else land at the lab between Prb shippments. It could easily delay the lab a couple of weeks after New Years to clear out the backlog.

A second possibility is that the the infill drilling is being incorporate into the resourse estimate to improve and expand the quality of the initial report. Once the initial leg work was done to model the property and writre the initial report the amount of work to revise it is relatively minor.

An Aside --- Once a property has been drilled for a while the geologists KNOW what mineralization looks like relative to grade. If you have competent geologists its unlikely to that a major surprise in grades would occur that only the lab would detect. It isn't unusual for drill crew that have been on a project for awhile to tell the geologists when they hit the zone and whether or not its a good hole. So while surprises are possible (especially on regional exploration holes) they are rare and rarer still to happen just at Xmas (but nice if they did indeed happen).

.... Been There