Chicken Egg orientation For Incubating

I just recently (7 days ago) began the process of incubating some of my chicken eggs. I learned today that eggs are supposed to be stored and incubated pointy end down to prevent bacteria from getting into the yolk. Most of what I can find online alludes to this being a very important detail. My question for you all is this. How important is it actually? and is it too late, 7 days in, to try and flip them over? I know I need to be turning them but will it hurt them to flip them completely on their heads now that the have already started to develop?

I know a lot of incubators, especially older ones that don't auto-turn, are designed for the eggs to just rest on their sides in a hatching tray. I'm assuming there was a enough success with that for people to keep producing and uysing those types of incubators. So as a second (or third?) question, is what really matters that the egg is NOT pointed pointy side up? not the the egg must be placed pointy side down?

Howdy!
Welcome to the fun of "But the experts didn't say I had to do it *that* way!"
I have yet to successfully use my brand-new not-even-out-of-the-box incubator. I lucked into having pullets who are doing that for me, right now (yeah, my flock isn't growing as quickly as it might.).

The reason for having the bottom of the egg up is twofold - the yolk might stick to the sides of the egg and the air sac is in the larger end.
For obvious reasons, it's better to have the air sac up so it's easier for air to get into the egg shell. Having the yolk stick to the side of the shell is a Bad Thing.

Having the eggs on their sides kinda covers your bases. By marking one side of the egg and flipping them every few hours it's easy to keep account of whether or not you rolled the egg over recently.
I'm sure there are experts here who can help you more, but I wanted to say hi (HI!), wish you luck with incubation, and tell you that, imo it's only too late to start doing something when it's obvious that the Bad Thing you were trying to avoid has happened. Up until then, who knows for sure?
Best thoughts for incubation!