Breaking up scenes

[Forlorn Radiance]

I don't know if there is a formal "right way" to do this, but I figure I'd ask better minds. In a lot of the books I read, if the scene changes, but the POV stays the same, they use a line break:

person doing something

*line break*
person does something else 20 minutes later

If the scene and the POV changes, they use an astrix/border:

person does something

***

another person does something else

My question is this: what if the change of scene is a flashback from years past? Does that count as a simple line break, or is that enough of a gap in the story to use a border? Ie:

Something happens to someone

line break OR ***

flashback

line break OR ***

Continue with previous scene.


Sorry if this sounds or looks a little awkward for a post, but I've been up for 96 hrs, gotta love my job.