That's entirely normal, because the scenery loading is not handled by FSX, but with our software modules, which allows for a lot more flexibility in setting visual ranges, multi seasonal changes, handling native FSX code, shaders, and reducing OOMs because, if we used the standard .BGL format, we wouldn't have any control on those elements, and FSX would just load everything.
It's not the scenery takes 3 seconds "more" to load. The final loading time is exactly the same, it's just that with other sceneries you don't notice it, because it's all hidden in the black screen with the loading scenery progress bar, which will of course take longer so, overall, the time to load the scenery is exactly the same.