Sorry Victor, took me a while to find the right person to answer this. This is what I was told, let me know if it helps:  "Victor’s interpretation is correct. We say in the course material that it is best practice to add 15% buffer to the calculated change rate. So the buffer should be added to the change rate given in the question. The actual question which has been quoted is straight from the course material, wherein a 15% buffer is added to the change rate of 17%. So the effective change rate used is 20% (0.17*1.15)*100 ~ rounded off to 20%."  
Hi, I am just a little confused with snap % change rate. Do we always add the 15% buffer to % change rate given in the exam or not? This is important for exam questions. So in the exam if % change rate is given do we apply the 15% buffer to this for calc e.g  Question in exam calc no of save devs with 200 vdevs assuming 17% change rate?  No buffer 200 * .17 = 34 savdev  With buffer 200 * .2 (.17*1.15 rounded up) = 40 savedev  and other calcs with % change rate do we assume the buffer is built in for calcs or do we apply the buffer for every calc  In the field I would apply the buffer but for the exam I want to ensure my interpretation is correct  Your help with this is appreciated  Victor
E20-326 Sym TA design - query on savedev calculations in exam