It could be the Amazon system thinking other services wouldnt get there on time. What is your handling time, when do you print labels and when creating label what do you choose as your dispatch date? My handling time is 2 days, I print labels same day order comes in but select 2 days from then as the dispatch date when creating labbels. Sometimes only EVRI comes up, I change dispatch date to that days date and all services pop up. I dispatch n 2 days as normal, customer gets their order by the estimated date, amazon bots sidestepped ;) If that doesnt work you could try creating labels sooner and setting your handling time higher in shipping settings but carry on dispatching as you normally do, just forces Amazons delivery window a bit bigger so it thinks all services would get there in time (and your parcels will generally arrive earlier than estimate so happy customers). Hope that helps, it certainly confuses Amazon SS as they email me quite a lot suggesting I ship same day so should change my handling time... they dont understand theres a diff between creating a label and dispatching ;)