You are either being mislead or not understanding exactly what they are telling you. Here's the deal, if the UPS store packs it, it is covered no questions asked, no hassle. If you pack it, insure it and it gets damaged, it's still covered, but they make you jump thru hoops to get the situation resolved. They have a habit of automatically denying the claim at first. They even automatically deny a claim although an item was packed in the original factory box(es). It is then up to you to fight them. I always take pictures as I'm packing, at the end of packing and of the sealed double box. When I pack an item, it will withstand a bomb blast. So, as long as you can show them proof that the item was packed properly, you will get the situation resolved in your favor.
The problem I have with them packing something like a heavy amp is that all they use is bubble wrap and that material will absolutely not stop a heavy amp from getting damaged. I've seen it happen way too many times. The boxes they use are single wall and they will not double box. Ummm...no thanks, that's almost a guarantee that it will get damaged.
Bottom line, pack it like your very life depended on it and as hard as they will try, it will not get damaged. After all, that should be what one really wants.
A doctrine fostered by a delusional, illogical minority and rabidly promoted by an unscrupulous mainstream media, which holds forth the proposition that it is entirely possible to pick up a turd by the clean end.
In a recent press conference, President Obama remarked, "If I had a city, it would look just like Detroit."