Ok, thanks again, I'll keep that in mind. Let's say this was just a soundcheck :)

It's not going to get your work rejected, so it's fine. Just something to remember for the future! No harm in editing, though.

Oh thanks, didn't notice that. Should I edit the submission then or leave it as it is? (If yes, I'll have to edit the second submission I made too. Ops!).

You don't have to upload a detail file if your entire artwork fits as the preview file. The detail file is optional, and it's for when you need to show more than what you can fit into the preview file.