Your numbers are a bit different from mine, and I suspect it is a difference in methodology. It seems you are taking the arithmetic mean of several weekly weighted averages. Is there a reason why the monthly weighted average is not used?
Revision:
Also, since we are talking about longer-period weighted averages, here are some data for various ranges.
One-day weighted averages:
1. 2013-04-09 through 2013-04-09 W. Avg: 214.67
2. 2013-11-03 through 2013-11-03 W. Avg: 206.50
3. 2013-11-02 through 2013-11-02 W. Avg: 204.22
4. 2013-11-01 through 2013-11-01 W. Avg: 202.61
5. 2013-10-30 through 2013-10-30 W. Avg: 201.05
Two-day weighted averages (overlapping permitted):
1. 2013-11-02 through 2013-11-03 W. Avg: 205.65
2. 2013-11-01 through 2013-11-02 W. Avg: 203.53
3. 2013-10-31 through 2013-11-01 W. Avg: 200.99
4. 2013-10-30 through 2013-10-31 W. Avg: 200.82
5. 2013-10-29 through 2013-10-30 W. Avg: 200.70
Two-day weighted averages (curtailed to avoid overlapping):
1. 2013-11-02 through 2013-11-03 W. Avg: 205.65
2. 2013-10-31 through 2013-11-01 W. Avg: 200.99
3. 2013-10-29 through 2013-10-30 W. Avg: 200.7
4. 2013-04-08 through 2013-04-09 W. Avg: 197.45
5. 2013-10-27 through 2013-10-28 W. Avg: 192.1
One-week weighted averages (curtailed):
1. 2013-10-28 through 2013-11-03 W. Avg: 200.94
2. 2013-10-21 through 2013-10-27 W. Avg: 185.09
3. 2013-04-05 through 2013-04-11 W. Avg: 175.81
4. 2013-10-14 through 2013-10-20 W. Avg: 147.77
5. 2013-04-24 through 2013-04-30 W. Avg: 142.27
Ten-day weighted averages (curtailed):
1. 2013-10-25 through 2013-11-03 W. Avg: 193.90
2. 2013-10-15 through 2013-10-24 W. Avg: 169.47
3. 2013-04-02 through 2013-04-11 W. Avg: 159.03
4. 2013-04-21 through 2013-04-30 W. Avg: 138.35
5. 2013-05-23 through 2013-06-01 W. Avg: 129.49
30-day weighted averages (curtailed):
1. 2013-10-05 through 2013-11-03 W. Avg: 167.28
2. 2013-08-31 through 2013-09-29 W. Avg: 124.57
3. 2013-04-20 through 2013-05-19 W. Avg: 120.72
4. 2013-05-20 through 2013-06-18 W. Avg: 116.84
5. 2013-03-13 through 2013-04-11 W. Avg: 108.63