You should use normally FormatNumber. Use this only if you want to read numeric values in your machine format.

FormatNumberEx('Wert', 'Format', '[N/Y] Kultur-abhängige/-unabhängige Formatierung', 'Dezimaltrennzeichen', 'TausenderTrennzeichen')

The third parameter determines how numerical values are formatted without specifying the two separators, e. g:

FormatNumberEx('12345.6789','0,000.00','Y') 

Returns' 12,345.68' on a German system and also under any other language, because the' invariant culture' is used.

FormatNumberEx('12345.6789','0,000.00','N')  

Supplies on a German system '12,345.68'

Hinweis: If the 3rd parameter is set to' Y', a standardised, culturally independent format is used (point as decimal separator, etc.).
If the 3rd parameter or' N' is not assigned, however, formatting is performed depending on the local language setting of the system.