OK, this is a bit more complicated. Apparently the decisive moment here is when you generate the file. Setting the data viewer to watch "GetAsNumber( "42.34567")" yields different results depending on which of the files that make up the solution is active. I will do more testing tomorrow and come back with the results.
So this is what we found: Where Getasnumber() is called to process a string like "42.123456" it will only recognize the decimal separator correctly if the format is the same that was set as system format at the time of file creation or cloning.
A German system uses the format "4,123456". A file build on a German system will understand "42,123456" but not "42.123465" regardless of the current system settings. Vice versa a file build on a system using the point as decimal separatorw will only understand this format, but not the current system format.
"Set Use System Format" doesn't help.