Hi. Our point of view about an event can be Before, During and After it.
In Hypothetic period, our REAL point of view is necessarily "now" (talking), but we can set our UNREAL point of view anywhere in time.
Because of this, for example, when Ancient romans wrote letters, they transformed their point of view into the reader's point of view, so that "today I am writing" became "the day when I wrote this".
-- Se avessi saputo del terremoto non sarei mai venuto in vacanza a Bologna in questo periodo.
= Here you imagine yourself Before "coming here" (UNREAL PV), supposing that with more informations, "being here" (REAL PV) would not have happened
-- Se sapessi del terremoto non verrei mai in vacanza a Bologna in questo periodo
= Here you say that After "being here" (REAL PV), you discovered that "in this period" always happen "earthquakes", so in the Future (UNREAL PV) you will not repeat "coming here in this period".
Common sense suggests that this is a bit nonsensical: earthquakes are not seasonal events; nevertheless, you can use this structure when it deals on Properties, something which is intrinsic of the objects in the phrase:
-- Se avessi il biglietto (NOW), verrei alla partita (TONIGHT)
-- Se sapessi la lezione (NOW), mi farei interrogare (RIGHT SOON)
Now I understand your doubt. Actually we use an Hypothetic past structure also for the Present
-- Se avessi saputo la lezione (NOW), mi sarei fatto interrogare (RIGHT SOON)
-- Se avessi saputo la lezione (YESTERDAY/ THIS MORNING/ NOW), mi sarei fatto interrogare (YESTERDAY / THIS MORNING/ RIGHT SOON)
What you should really care to, is how the Protasis (First part) and the Apodosis (Consequence) relate to each other: this is the real matter of Hypothetic sentences.
If you keep yourself trained with Hypothetic Period, you will understand a fundamental part of Italian.