How can I account abandon in my calc

Monthly Volume = 25000
AHT = 10 mins
Service Level = 90% < 20 secs Shrinkage 12% Occupancy = 75% 40hours/week With the given info: I can calc my FTE through (((25000*12/52)*10)/60 / (1-12%) / 75%) / 40 = 36 FTE Can you help me how I can the take the SL to my calc or my abandonment to calc which is at 2% abandonment. Can I apply the abandonment directly to my monthly volume? which will reduce it at around 500, by doing this its like me saying that we will not be able to answer that 500 calls due to application of the abandonment. Im not quite sure if this is logical to do or how?