smart:limit always tries to find the right dynamics for a track, since the targeted dynamics are defining the amount and style of limiting. When smart:limit learns new limiter settings, it looks at the chosen genre profile as well as the input signal and tries to find settings that lead to good dynamics for this specific track.
The loudness is a direct result of the targeted dynamics. So smart:limit is using the dynamics value and not the loudness value as a learning target. It doesn't make sense to aim for a certain loudness if it doesn’t fit the style of your track (e.g. make a pop track overly-dynamic simply not to become too loud). Therefore, the selected publishing target will be ignored during learning.
So what about the loudness publishing targets?
The loudness publishing targets simply help you in finding the right (minimum) loudness for publishing. For some in-depth information on loudness normalisation for streaming platforms, check out this blog post.
Loudness & Streaming Platforms
Almost all streaming platforms normalize every track to some reference loudness (e.g. -14 LUFS for Spotify). So while it would be a bad idea to sacrifice dynamics to make a track really, really loud that will be turned down later on anyway, making a track louder than the reference is no problem at all.
Yes, it will be turned down – but so is every other track. Every track is normalized to the same perceived loudness level, meaning that no track is louder than another after normalization.
It’s only important not to fall BELOW the reference loudness of a platform. If a track is too quiet it will be turned up - and that can lead to unwanted limiting. That’s why smart:limit's Quality Check qualifies all loudness values above the reference loudness of a streaming platform as good.
Hint: If you want to, you can turn down the track to a certain reference loudness using the linear output gain of smart:limit. But please note that the end result on the platform will not change, since the platforms will also simply linearly turn down the gain. ;)
Loudness Standards suggest an actual target loudness (not only a minimum reference loudness). As a consequence, all loudness values above or below the loudness target of a loudness standard are potentially a problem and smart:limit will show the respective warning when using the Quality Check.