The Excel charts are saved as PDF and then imported into FrameMaker 2015, into pre-made frames. The frames act as placeholders until the PDF pages are imported. Is there a way to automatically scale the PDF pages to fit into the pre-made frames upon import?
not an answer … but I'll watch this thread with interest in case someone explains exactly what "Fit in selected rectangle" is for :-} I'm groping towards a working understanding of how to use this option, but it feels like a very strange workflow.
If the .XLS documents open cleanly in LibreOffice or OpenOffice Calc, it might be a better tool to export from.
Calc can trivially Export, as PDF/A, using (*) Selection. That plus control over what would have been the print page size will allow you to consistently export a PDF object sized for the Anchored Frame. The content remains [searchable] text, vector art (if present) and whatever raster art was present, so full quality.
If you are using the PDFCreator add-on to Excel, then all of the charts are exported to letter-sized PDFs and are scaled based upon your specified option in Excel (Actual Size, Fit to paper width, Fit Worksheet to single page).
If all of the charts are the same size, then you could use an Object Style on the imported graphic to both scale and position as desired. IF the charts are different sizes, then it might not work that well as you may require quite a few Object Styles to cover all sizes [you can create any number of Object Styles, but this can get out of hand quickly].