Using the words "post facto" [closed]

How to use the term "post facto" in a sentence?

There is an oversight to our standard procedure of seeking approval to process some invoices. I am sending a reminder to concerned about the process and telling them that

I will seek post facto approval for this instance but in future all procedures must be followed.

Am I using the words "post facto" correctly?

"Post facto" is used attributively denoting "after a certain event", so I think it is used here correctly. However, I feel that "post facto" is more of a legal term, and in other cases the spelling "post factum" is usually used.

Don't use Latin words at all unless you have a goood reason. In this case, the English word you want is restrospective, which has the advantage of being more likely to be understood.

You also probably want to say a reminder to those concerned.