it's possible that your f1graphics gets adjusted. somewhere in the csm.ini file there's a line called f1graphics which could change values in the f1graphics file.
it probably looks something like:
1,,,,,1,,,,640,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,
where all comma seperated values are optional. each value represents a new line in your f1graphics.cfg. if something is left out it will pick the default setting.
you can create such a line with the f1graphics.exe tool located in the zaz tools folder. use the checkboxes to export certain settings and the copy to clipboard button to set the line on your clipboard.
I'd rather have a bottle in front of me than a frontal lobotomy