Hi:
I'm not sure you can change the borders the way you envision with a style override. Also you're using "old style" style overrides for in-line formatting, and that may or many not work, depending on your destination, which you did not show. Are you wanting RTF, PDF or HTML or ??? I am pretty sure that you're not going to be able to change the borders like this if you want ODS EXCEL output.
Do you only want the thicker line in the header??? Don't you want the thick line to go down the entire column? Just curious, it would bother me to see a thicker line in the header that wasn't carried down the whole report. And it might not work, again, depending on your destination. Also a border width of 1 without a unit of measure is only 1 pixel, which is the default unit of measure, so that's not going to be very thick. Also, your description does not make sense to me. You are labelling variable Q08 and Q12, etc as Q4, And everything is a usage of DISPLAY which makes me wonder whether you've presummarized the data from some other structure into this structure for the report.
Can you provide a bit more context for your report?
This is how I would alter the borders if I wanted ODS HTML:

Cynthia