Is the estimate of the prediction time exact?
No, the estimate is an estimate. It can be relatively accurate for some methods (IDW/automap), whereas the uncertainty is larger for psgp and copula. This is for three reasons. First of all are the time models generated from a simulated data set, different observations and configurations can influence the time. Most important is that psgp and copula methods estimate the parameters through iterative search procedures. Different paths can be used for finding the parameters, and different data sets can influence the convergence of the optimization routines. The last cause of differences is that most methods can fit a range of models to the data sets, and the choice of model will also influence the prediction time.
