Kolsch recipe from BYO?

Hello I am looking into brewing this kolsch recipe from march- april BYO. But I have a ? about the fermentation they are using for this recipe it say to ferment at 62F for the first 3 days an then ramp to 68F over 10 days. Now I know to hold it at 62F for 3 days but how many degree’s per day am i ramping it up through the 10 days so on the tenth day I am at the 68F

Half a degree per day is close enough.