Does a traveler pray a shortened prayer if he travels for work for one or three months with a one-week vacation, and then returns to his city?

"Whoever intends to reside in a country for four days or more is obligated to pray in full and is not permitted to shorten the prayer. Accordingly, if you travel for work to a certain country and your stay there is four days or more, you are obligated to complete the prayer. As for your hometown, you become a resident there, and you are required to complete the prayer as soon as you arrive."