Sounds like a local thing. At our congregation you can order as many as you want.
Maybe at that particular congregation some were ordering 10 or 20 each, and then not picking them up after they arrived?
You are correct, reading the text is no longer done at meetings for field service or at assemblies.
Don't know why they stopped it at assemblies.
It was stopped at meetings for service because it was a "crutch" for the conductor. 90% of the time the text had nothing to do with field serve-us, but the conductor out of laziness would cover the text anyway. Now, the idea is, the FS conductor has to talk about "how to present the magazines" or whatever - something more practical.