Nothing new about this scenario. You see a nice item in any manufacturer's catalog and decide to order it. You patiently wait for it to arrive and when you open it is not exactly what you expected. I have several of the older MTH flatcars with Shermans and think they are GREAT! I believe those tanks are 1:48 (maybe 1:50) but they look corrrect when alongside 1:48 Jeeps.
The Shermans on the latest flatcars are 1:43. They are fine models but they are significantly larger then the first run of Shermans. I am the picky type that can't run these flats in a train with the smaller Shermans. My wife, and I imagine most people would think that is ridiculuous, but I am just wired that way and can't mix the sizes.
In the whole scheme of things this is nothing to get worked up over, it is simply aggravating that manufacturers don't do a better job of expliciting describing the product they indend to produce and then deliver that exact product.
Now I will simply have two shorter Army trains than the one long one doubleheaded that I had planned...bit of a bummer. The ambulances are also 1:43 and to my eye look silly next to 1:48 Jeeps. So in the end, buyer beware or lower your expectations.