In terms of getting the best quality, F&M Expressions and other serious printers are correctly separating the halftones from solid color. Halftones and solid color do not necessarily use the same mesh count. The problem is that when you try to lay down a nice even solid color, the halftones that are on the same screen may suffer from dot gain and become darker or fill in creating a mess. If you try to cater to the halftones on press, then you will possibly lay down a very light ink in solid color areas. The way you treat both correctly is by having a separate screen for halftones vs solids.
F&M are doing the right thing for maximum quality.
Of course the cheaper and lesser quality route is to put it all on one screen. I do it constantly but you may wrestle with it on press or settle for a lesser quality result. F&M Expressions is not trying to gouge you. Some printers absolutely default to the cheap route because quality was never their intention. Just getting the job out the door and getting the next one on press is all they can think.
Separating solids from halftones is probably even more necessary for transfers than for direct screen printing.
