I have spent a fair bit of time trying to find a solution to this problem and all I have found is other people who have the same issue but no solution. I have a spreadsheet where I cannot change the format of a cell from -1,000 to (1,000). See the attached screen shot that shows the choices I have. Also, in some spreadsheets I have there are numerous "custom" choices where I can pick the format that gives me what I want but in other sheets there are far less "custom" choices. Not sure why that is either. I hope you have run across this before and can explain it to me.
My understanding is that what is offered in the numberformat for numbers and currency is dependent on regional settings.
I would assume the default for built in custom number formats could be dependent on regional settings as well. I don't have first hand knowledge because I only use US English.
Nonetheless, you can make a custom number format and it is retained in that workbook. That might be why you see a bigger list in some workbooks. When a user makes a "custom" custom number format, it is saved in the workbook where it was created.
This article goes over what you can do with custom number formats:
Now one thing you could try is to go into the control panel in windows and change some of your regional settings. You can select options for the display of numbers in the control panel (this is a windows setting - not an excel option). In my settings, negative currency is shown as parentheses. Perhaps if you chose that, it would change what Excel offers. I know excel is sensitive to many of these windows level settings.
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