I solved the problem! Iām going to write here the solution:
In the standard calcuation (USA-local) ā0ā is the first day of the week (sunday), and the week 1 starts from January 1st
In the ISO calculation the week starts from January 4th
So you have to change the value of two variables in these files for the correct calculation:
cache\include\javascript\sugar_grp1_yui.js
cache\include\javascript\sugar_grp_yui_widgets.js
include\javascript\yui\build\calendar\calendar.js
include\javascript\yui\build\calendar\calendar-min.js
include\javascript\yui\build\datemath\datemath.js
include\javascript\yui\build\datemath\datemath-min.js
firstDayOfWeek = firstDayOfWeek || 0 ----> firstDayOfWeek = firstDayOfWeek || 1
WEEK_ONE_JAN_DATE : 1 ----> WEEK_ONE_JAN_DATE : 4
Then the Week Calculation is correct (for ISO)
Good afternoon !