ABC Call Volume Analysis Assumptions

Hi, I have been doing my Project 8 - Call Volume Trend Analysis. In task 3 and task 4, we need to find the number of agents we needed more so that the abandoned call rate comes down for day and night shift. So, the thing is some assumptions are given at bottom of the tasks but during my analysis, I don't think that I would need to use those assumptions since we are required to find the number of agents that should be there to take up the calls. So, my approach is : number of calls attended by an agent per hour = number of calls attended per hour / number of agents available per hour then find the calls per hour during night shift & calls abandoned in number (or percentage) and then divide it by the average of number of calls attended by an agent per hour So, is this approach acceptable or should I use the assumptions only. Note: Both the approaches will give different results. My approach uses the number of agents actually are available at the time by counting the agent_id for that hour so the time when the agents don't attend the calls is included in finding the number of calls attended by an agent per hour. The appraoch using assumptions will find the same without including the time that the agents were not attending the call.