2.1.704 Part 1 Section 18.8.31, numFmts (Number Formats)
a. The standard does not describe how to interpret a number format with only three sections.
If only three sections are specified, the first is used for positive numbers, second for negative numbers and the third is used for zero values in Office.
b. The standard states that the & (ampersand) text operator is used to join, or concatenate, two values.
Excel displays '&' if '&' is present in the format.
c. The standard states that if the cell contains a number between 0 and 1, the application shall multiply the number by 100 and add the percentage symbol in the cell (for Percentage formatting).
Office applies percentage formatting to any numeric cell value.
d. The standard does not include an entry for '/' in the table of format characters.
In Excel, the fraction format character ('/') displays the number in the format of a fraction. It is interpreted as the fraction format character only when preceded and followed by a number symbol (0, #, and ?).
e. The standard lists e+ and e- along with E+ and E- as the format characters for specifying use of scientific notation.
In Office, only E+ and E- are the format characters for specifying use of scientific notation.
f. The standard states that date format codes e and ee become yy in all locales other than JPN/CHT.
In Office, date format codes e and ee become yyyy in all locales other than JPN/CHT.
g. The standard does not limit the number of custom number formats defined in numFmts.
Office limits the number of custom number formats to 206 and also persists files that contain more than 206 custom formats (which it cannot load).