What is the max number of weeks limit for harmony test to be taken?

Week 13 now, my FTS result is low risk, but I would like to consult the doctor on the need for a harmony test as I don't understand the report other than knowing its low risk and not sure if I should go for harmony test as the accuracy is higher but my next gynae check up is on week 15. Is it too late to do a harmony test after week 15? Is there a max limit ? My result as per attached.