This works in both directions. Sometimes you can source a part more cheaply than the estimate, in part because the sourced part is lower quality than what Apple uses. Sometimes you can't source a part as cheaply as the estimate, because the estimate is assuming Apple can get the parts at a scale we can't touch.
Basically, these estimates seem like wild guesses.
That’s still a significant percentage to now be dependent upon a country that could end up with huge tariffs. I enjoyed their actual breakdown of price by component, but I wasn’t so much concerned with the actual number... just that being “made” elsewhere was all the mattered.