I'm moving out of my current place in a few days. When I'm doing something a little annoying to my roommate, I joke, "sorry, this is (will be) like the 4th last time I do this", to mean that I'm only gonna do it 3 (a few) more times, so don't sweat, and forgive me. Am I using "4th last time" right?
I read the statement
"this is like the 4th last time I do this." to mean you have stated
"this is the last time I do this" three times already.
Unless you have said this three times, then I would say you are not using the word
"4th" correctly in this manner.
If you are trying to say
"I am only doing this three more times", then you could say the phrase
"sorry, I have to do this three more times."