Maximum and Minimum Value in a Report

[#1]

I want to customize my CPU Utilization and Memory Utilization Report. Normally the reports display the average value over the period of time. like in CPU Utilization i have average utilization for a month or week for my Infoblox members. What i want to do is to generate a report that only displays two values i.e Maximum and Minimum over the giveb period of time. 

Suppose for CPU utilization the maximum and minimum value in last week. 

Currently default serach is below:

index=ib_system_summary report=si_cpu_usage (orig_host="*rwp-iba2-ib4030-dns-1.ptcl*" OR orig_host="*rwp-iba2-ib4030-dns-2.ptcl*" OR orig_host="*rwp-iba2-ib4030-dns-3.ptcl*" OR orig_host="*rwp-iba2-ib4030-dns-4.ptcl*") | timechart bins=1000 avg(CPU_PERCENT) by orig_host where max in top5 useother=f | interpolate 1200

I tried to call the max function but didnt get the fruitful output. Please guide me how can i play with above search to get my desired output. 

Thanks in advance.