Rolling Period Formula

[JoshM]

My firm and I need to know if there is an array formula (or combination) in which tells us how many times (occurrences) a unique value (such as an account number) experiences fees (such as a fee code) within a rolling time period we specify (such as two weeks). I'm an Excel power user, but this problem is bedeviling me. Thanks for anyone's consideration.

 

[MARK858]

One way possibly (please note dd/mm/yyyy format below)...

Excel Workbook
	A	B	C
1	item	Date	Rolling
2	2	15/03/2014	2
3	3	18/03/2014	5
4	4	21/03/2014	9
5	2	24/03/2014	11
6	3	27/03/2014	14
7	4	30/03/2014	16
8	6	02/04/2014	19
9	2	05/04/2014	17
10	1	08/04/2014	16
11	3	11/04/2014	16
12	5	14/04/2014	17
13	2	17/04/2014	13
14	3	20/04/2014	14
Sheet1