I am facing the same problem regarding calender weeks.
The week starting from January, 2nd and ending on January, 8th is shown as week 52 in Touchdown. Week 1 starts on January 9th, week 2 starts on January 16th and so on. That is totally wrong.
I know there are different definitions for calender weeks, but I do not know any definition that will call the January, 9th as the beginning of week 1!
I believe that needs to be corrected and while you add it you might want to implement calender weeks calculation according to ISO 8601 as well as the US system.