Re: atemi at end of technique
I believe the technical term for this strike is a todome and I think you could argue that this is not an atemi at all; there is no further need to fix or shift uke's balance, create an opening, or anything other than make it unlikely that they will ground fight or get back up.
I think todome are not entirely appropriate in a non-kata-oriented setting. Indicative of a cockiness that you should be on the mat trying to tame. The only specific instruction I have received is with regards to knife and sword taking, you don't cut uke with his weapon after you take it, though.