Surely if some sums of money have been in there longer than others simply dividing all the monies by all the days would not give an accurate representation of the overall average!
I have various income flows
1000 for 173 days
9000 for 153 days
20000 for 123 days
30000 for 62 days
30000 for 31 days
what I am hoping to achieve is to find the average value over the given period, that period being 173 days