ALV Grid ColumnType F display

All

Easy one this surely...

I wish to display a column in the ALV grid formatted to 2 decimal places with no exponent. Therefore, as the doucmentation suggests, I have specified the following in my field catalog definition:

if p_fieldname = 'PERCENT'.

gs_fieldcat-decimals_O = '2'.

gs_fieldcat-exponent = '0'.

endif.

The field percent is defined as type f.

However, both fields are completely ignored and I have resulted in creating another type c column and WRITEing the result into it. The if statement is sound as I debugged it and all is well. I added the gs_fieldcat-exponent-key = 'X' option to test it as well and this was fine. I have also tried the two options on their own but no difference, I still get 1.000000000E01 etc

What am I missing? I am on 46B BTW.

Any clues?

Ian