Average Function: Multiple Arguments

I need some assistance in using an array formula which averages based on multiple arguments. The relevent range names in my input data are:

Col A - Manager Col B - Report Type Col C - Days taken to Complete

and I have used Validation Lists to include several different Managers and 5 Report Types which I'll call A - E, with Days taken to Complete an input. Each Manager may have 0 to numerous instances of each report during each period.

I'm trying to build a table which includes each manager and the average number of days taken to complete each report. The complication is that, while Report A & B are separate reports, for this purpose I need to get an average for A & B together.

For C, D & E, I have used the following:
{=AVERAGE(IF((Type="C")*(Manager="Smith"),Days_taken_to_Complete))}

For A&B, I have tried:

{=AVERAGE(IF((Type="A")*(Type="B")*(Manager="Smith"),Days_taken_to_Complete))}

but this doesn't work. Could someone please advise me the correct formula if either of two states in a named range are to be used to average a second named range?