Ok. I haven't done paper forms for this sort of thing in many years, so I am not sure how that sort of transaction goes anymore. I have mostly done online with CC. Generally, vendors hold off charging until an item ships as that keeps them in the good graces of the credit card company and customers. This can be a problem if you get a bad charge/charges elsewhere in the meantime, and are issued a new card...all-too-common over the past 10 years, this probably happens to us about once every 1 to 2 years on some account and is quickly flagged.
The web-site info (or possibly something specific to browser cache) is not always in-sync from what I have seen. This is true of some websites after normal business hours (for the stores) in particular, not necessarily Astronomics, just an observation. I swear that at some sites I have sometimes seen items show as in-stock during the night, and out-of-stock during the day, repeatedly. Calls during business hours to some websites always show the items to be out of stock. For months a Google search for the AT72EDII has shown it as "in-stock" in the summary, before clicking the link that shows "more on the way" even though I have done browser cache purges. There are a lot of vastly different web sites and items that show one availability or price in the Google summary list, and something totally different in the link so checking during business hours is advisable.
The AT scopes come in en masse in shipments from what I have gathered, but I don't know that all types arrive at the same time (and the manufacturers may differ depending on the model for all I know and therefore arrive separately.) I don't think there are any small interim shipments happening, but that is only my impression based on what I have been told. I would expect they prepare shipping labels and such in advance to accelerate a time consuming process of filling/shipping back orders when the physical shipment arrives.
There are going to be some orders that go in queue before the availability goes to zero. That is where I think mine was, because I was shocked when it showed up out of stock the next day. I had been watching it and finally decided to pull the trigger. I blamed myself for recommending the scope to others, while holding off actually ordering one because I didn't necessarily "need" it.
They also take some pre-orders, but I don't want to speculate on the criteria since it likely varies based on history with the product/maker/model.