Cell format not applied after file reload in Calc

Hi:
I created a particular numeric format in my file, which I called TwoDig (see below)

The format worked as expected, as you see below.

The problem shows when I save my file and open it again. I looks like the format disappeared!

When I check the format cells menu to see if my TwoDig format shows, this is what I get:

The question mark character was removed from the format! Is this a problem with the software or I’m doing something wrong? Please, help. Thanks.

In what format are you saving your spreadsheet? If you are not using the native .ods you may lose formatting.

I’m using native .ods

Hi:
This problem is solved if I save the file in .xlsx format instead of .ods. Strange!