Ok, according to this website :
"should" can be used to show mild obligation or advice
Ex: You should save some money.
"should have + pp" can be used to show advice in the past (that past action didn't happen)
Ex: You should have gone to bed earlier, now you have missed the train.
After spending 3 days googling, we found that we also had the structure "should + be + verb-ing" to express that the subject is not fulfilling their obligation or is not acting sensibly.
Ex: You should be wearing your seatbelt. (The person isn't wearing one right now)
We should be studying for the test. (We are not studying right now and we should)
This seems to make sense because "be verb-ing" expresses an ongoing action.
My question is that:
Do we have the structure "should have been doing" (advice in the past) in everyday English conversation?
Can we say:
Ex: You should have been wearing your seatbelt at the time the plane took off. (The person wasn't wearing one at that moment & we said this to express a regret in the past)
Note: I couldn't find any source on the internet mentioning this, so could you please include a referenced source in your answers?