I do this stuff on an almost daily basis at work, usually with the USA and the Far East, and tear my hair out fairly regularly. My comment on
some American companies is not intended to be rude - it is based on reality. I am sure that if we were importing stuff from Mongolia we would see the same or worse problems, but we are not importing stuff from Mongolia.....
It's certainly true that sea freight should be cheapest, but the reality is that air freight is often very close. Don't ask me why. How can a ship be anywhere near a 747 in cost?? Consolidated SF can be very cheap but can take 1-2 months plus the transit time.
And AF is simpler. With SF you need the sender to send you separately (usually by Fedex etc) the original airwaybill, without which you cannot claim the goods when they turn up. With AF the stuff simply turns up....
Unfortunately shipping companies are not the sharpest knives in the drawer and mess up quite often. In the big picture they are fine but they have a habit of messing up when it's least convenient... That's why I would recommend using Fedex or similar and having a drink of something strong before seeing the invoice
