A question about a recipe: Italian Style Boule

I have a question about step 8 on the recipe "Italian Style Boule" from boulangere. It says:

"This part goes fast: just before you put the bread in the oven, pour the hot water into the skillet if you have one, and carefully set it on the oven floor. Slash the bread diagonally 3 or 4 times with a serrated knife held at an acute angle. Get the bread into the oven. Set a timer for 15 minutes. Don’t open the oven until it goes off. Then, re-set the timer, open the oven and quickly rotate the bread 180 degrees. The bread is done when it reaches an internal temperature of between 200 to 205 degrees. A boule will take about 5 minutes longer than a baguette shape.
After the timer goes off and you rotate the bread you say to reset the timer, for how long? I assume another 15 minutes but I could be wrong.