Can Op submit the calculation and leave out the last time they left, and then ensure that in the address line, they put where they currently live (which would be outside Canada)
So I assume this person has enough time as a PR in Canada and can apply, I would also suggest putting a letter explaining why your address is listed as outside Canada and why you did not include it since there is no return date.
So the question would be, since the last time you left did you meet the 1,099 days?
This is just my suggestion, not sure how viable that is, but if you were elibale b4 you left and has maintained your RO then you should be good, to submit without proving your current time out of the country on the calculation it self, as the application would have a section to put the current address, and you also need to have a Canadian address when you apply as well.