@PhilHarrision, Making it 1st of months is not a good idea. Lots of months don't have the first day of the calendar month aligned with NPD month. Example : 1 April 09 fall into March NPD, while 5 April fall into April NPD. 1 May 09 fall into April NPD< while 3 May fall into May NPD.
It is better to use 10th day as filler date, since it always fall into the same NPD month. So March 10, 2010 is a better date compared to March 31 or March 1.
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Making it 1st of months is not a good idea. Lots of months don't have the first day of the calendar month aligned with NPD month.
Example :
1 April 09 fall into March NPD, while 5 April fall into April NPD.
1 May 09 fall into April NPD< while 3 May fall into May NPD.
It is better to use 10th day as filler date, since it always fall into the same NPD month. So March 10, 2010 is a better date compared to March 31 or March 1.