On the grid from CMS it shows typical time for 99201 as 10, threshold time to bill 99354 is 40, threshold for 99354 and 99355 is 85. 10 + 30 +30 = 70 so we have an extra 15 minutes. I figure this is because we do not code for the first 15 minutes, but cannot find documentation from a reputable source to explain the 15 minutes.