They're giving you that option - to pay more in shipping to get what they have now, or to wait until it's all in.Mea culpa. I went back and read their email, and that is how it was stated; though I think waiting for 3 types of ammo to be in stock simultaneously might make me wish I paid for the multiple shipping fees.
You say "might make me wish" ... no need to wish - if you want it NOW then follow their directions.
You may want to edit your other post to rescind your negative view of Midway as obviously the issue was on your end with understanding the written words sent to you in the email by them.