ONE LOSS TREND QUESTION

[judal]

IN PAGE 301 OF WERNER, regarding the loss trend. I thought both trend from and trend to in this example is by PY. Therefore, looking at experience period PY 7/1/03-04, the ave loss date is 7/1/04, and for the trend to period, which is also an annual policy effective 7/1/2009, the ave loss date is 7/1/2010, right?
while in page 301, it said the ave accident date of trend to period is 12/31/2009, similarly, all the trend from period, the ave accident date is 12/31. How come?
also when ever after trending, and you need to apply the LDF, which LDF to use. For example in the above example, for PY 7/1/03-04, after trending for 7/1/2009-2010 period, which LDF you use, how did the example comes up with the LDF of 66 to ultimate?

Thanks in advance.