2.1.665 Part 1 Section 188.8.131.52, filters (Filter Criteria)
a. The standard states that the filter and dateGroupItem child elements should be sequenced.
Excel requires these child elements to be a choice of one or the other.
b. The standard defines the calendarType attribute for date grouped items.
Office ignores the calendarType attribute.
c. The standard states that the calendarType attribute is of type ST_CalendarType, which has a value for "saka".
Office does not support the ST_CalendarType value of "saka" and instead treats the "saka" value as equivalent to the "none" value of ST_CalendarType.