Yes, basically.
Load Line Calibration is the classic remedy against Vdroop, i.e. a sudden drop in CPU voltage when the load suddenly increases, and is used especially when you want to overclock (not that most CPUs are any good for proper overclocking anymore, nowadays OC often just ruins their efficiency further). LLC is to prevent the manually set VCore from dropping too much under load, and the overclocked-or-otherwise-tuned CPU becoming unstable from too much voltage undershoot (or negative overshoot, however you wanna call it). LLC can minimize the voltage differences between idle and load. But if overdone, it can lead to an unnecessary high voltage in idle.
The voltage decreasing under load, that is a normal "feature", meaning it is the normal behaviour, not something that should always be fought against. But if you determined that you need to use LLC (for example when it otherwise becomes unstable with whatever your settings are), then it will work against that sudden voltage drop under high load.
Usually the modes are something like this:
The "No OV" is the default curve, that's how the CPU and VRM behave normally. On the X-axis you see the amount of load for the CPU, on the Y-axis you see how VCore behaves. With "No OV", VCore is allowed to suddenly decrease with high CPU load. That is primarily so that when the high CPU load suddenly stops again (as it would), the VRM doesn't keep pumping in lots of juice into the CPU for a split-second and causes the VCore to exceed the specifications. Because the VRM is never as fast as the load changes on the CPU, it always takes a bit of time to adjust to a new load situation, it "oscillates" on any sudden load changes. And when you go back from heavy load to light load, this oscillating VCore - if there was no Vdroop - would make the voltage spike above the specification for the CPU.
This is an illustration from Anandtech about that:
View attachment 181196
When suddenly going from light to heavy CPU load (which is also called a transient load), there is Vdroop, so that once the heavy CPU load stops, the VCore doesn't spike above spec. In other words, with the "No OV" setting (which should be active when you leave LLC on Auto and haven't touched VCore either), the board will prevent VCore from exceeding spec after transient loads and potentially damaging the CPU over time.
But there can be situations when this Vdroop is not wanted, when you have changed VCore (by whatever means, there's several), and suddenly this Vdroop makes the voltage drop too much under certain load situations. Then you can set LLC to counteract it.
Again looking at the graph from the MSI BIOS, Mode 8 would be minimal LLC, just counteracting Vdroop a little. Then the higher you go, the more it will try to prevent Vdroop. And once you go to Mode 2 or Mode 1, it even overcompensates, meaning now VCore will even shoot up a bit higher with sudden high load, so the normal behaviour is more or less reversed. That would be extreme LLC, there are very few cases where such a behaviour would be needed. Most people will probably stay between Mode 3 and 6, i'd say.
