You're able to set up multiple Master Profiles for different situations. For example, I use three of them - one for Free Shipping, one for Free First Class with a flat rate Priority upgrade, and one for calculated weight-rated shipping (I just fill in the weight) for heavier items.
When you're doing a 'fresh from scratch' listing setup, you have to select which Master Profile to use on that listing. Otherwise, you will have to fill in the info every time. (It took me a day or two to figure this out when I started, too, so don't feel bad.)
If you're listing a batch of similar items (Charms, for example) to which the same general and shipping info applies, it gets easier as you go. Once you have the first listing set up, including the appropriate profile, and saved - then you can select that listing as the basis for Create A Similar Listing. The listing screen comes up, pre-filled with the info from that base listing. Just change the Title, Description details, Pictures, and Price, as applicable for the new item, then Save it. Now you have two item listings saved - with the second one having copied its Profile info from the first one (as well as anything else you didn't change - such as Template selection). Repeat the process for additional pieces.