I have 10 sites in my Google Analytics account, and each site has their own Property Tracking ID.
There's an option called "All views associated with this account" in the Views section in Custom Report (customization), which allows me to select all 10 of my sites. But the Line Chart and all info in this Overview only shows my main site. Is there something I missed, like a configuration?
Views are linked to a tracking ID. It does sound like when you're creating a custom report that it's going to select all profiles within your account but in reality, it is going to get all views linked to that one tracking ID.
When you create a custom report, look in the top right below your email address you'll see which Profile you're viewing.
Try googling analytics custom report multiple profiles
