It is common to have expectations like being in high ketosis after a 12 hrs fasting period, or eating "just right" according to all blogs ...

Ketosis is not only dependent on what you eat and don't eat, there is a lot of factors that play a role in your body's use of fat.

Using a low-carb/ketogenic diet for a long time, will make your cells fat-adapted. Sure, your body will use fat more easily, but the fat to energy
does not need to take the route via the liver making ketones.

To make your body burn excess fat, you need to trigger that process. When you're fat-adapted, the  intramuscular fat is mainly used, and not the visible fat we want to use.
By "triggering" the use of the stored fat via the liver, we can elevate ketosis.