Bert, we all should know that computers work in a borning, linear, one-step-at-a-time way. So how is your computer supposed to know how big a new file is before it has had a chance to download it and "see" how big it is?

Sure, they try to give you an estimate. You've got to keep in mind that this is aimed at people on the job. For them the critical question is, will my computer be down long enough for me to -

a. hit the restroom
b. make microwave popcorn
c. call a client?

While 19 minutes isn't much different from 14, 19 is a lot different from, say, 59.