Calculate a list of Averages from a Timesheet

[LWLSKOP]

Hi Guys

I want formulas that will calculate a summary of averages from the timesheet below(actual spreadsheet has over 50,000 rows with 12 employee). My aim is to be able to see, when I expand each subtotal/month, the average hours worked per day/week/month for the month/subtotal and in the same manner as the number of counts for all employees - summarised below the table (highlighted yellow).

In other words, each subtotal will have its summary of averages below the table when I collapse it. Cells without data should be ignored in the formula

Many thanks

			FELIX	RICHARD	GRAND TOTAL
MONTH	WEEK	DATE	START	END	HRS WKED	COUNTS	START	END	HRS WKED	COUNTS	TOTAL HRS WKD	COUNT
1	2	08/04/2014	-	-	-	-	12:56:05	15:42:30	2:46:25	95	2:46:25	95
1	2	09/04/2014	-	-	-	-	10:20:26	15:45:52	5:25:26	87	5:25:26	87
1	2	10/04/2014	9:59:13	13:52:33	3:53:20	100	-	-	-	-	3:53:20	100
1	2	11/04/2014	9:20:09	10:18:30	0:58:21	60	-	-	-	-	0:58:21	60
1	3	14/04/2014	-	-	-	-	12:25:45	13:37:04	1:11:19	77	1:11:19	142
1	3	15/04/2014	-	-	-	-	10:25:35	11:38:00	1:12:25	54	1:12:25	271
1	5	28/04/2014	-	-	-	-	11:05:02	14:25:40	3:20:38	79	3:20:38	79
1	5	29/04/2014	-	-	-	-	13:40:21	15:10:56	1:30:35	76	1:30:35	76
1	5	30/04/2014	8:05:57	10:34:43	2:28:46	114	-	-	-	-	2:28:46	167
1 Total					7:20:27	274			15:26:48	468	22:47:15	1077
2	5	01/05/2014	-	-	-	-	9:51:10	10:31:51	0:40:41	26	0:40:41	26
2	6	06/05/2014	7:48:15	9:30:25	1:42:10	89	-	-	-	-	1:42:10	89
2	8	19/05/2014	9:25:05	11:02:22	1:37:17	85	-	-	-	-	1:37:17	85
2	8	20/05/2014	8:36:57	9:23:18	0:46:21	42	-	-	-	-	0:46:21	42
2	8	21/05/2014	9:36:35	11:26:12	1:49:37	54	9:30:50	13:11:51	3:41:01	91	5:30:38	145
2	8	22/05/2014	8:56:13	9:03:00	0:06:47	3	-	-	-	-	0:06:47	3
2 Total					6:02:12	273			4:21:42	117	10:23:54	390
											Average Time Spent/Day	?
											Average Time Spent/Week	?
											Average Time Spent/Month	?
											Average Counts/Day	?
											Average Counts/Week	?
											Average Counts/Month	?
											Average Start Time	?
											Average End Time	?

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