Check box and Radio Button values not exporting correctly despite correct appearance

I've created a PDF form in Adobe Acrobat X Pro and am sending it out for large numbers of customers to fill in. We ask them to use Adobe Reader to complete it, but they don't always. Sometimes, when the customer completes the form with different software (all the examples I've checked have been itext-paulo-155) the information is visible but doesn't export, either to csv, fdf, or using the getfield().value in VBA on a JS object.

From looking around the web, it seems that the issue is the separate setting (or not) of the field values and appearances. The checkbox appears checked, but exports as Off, and if you click on it once it becomes checked (apparently indicating that it was not already checked). I've tried updating the field properties to force the field to update its appearance, but this just causes it to appear Off. Similarly, exporting the form data to FDF then reimporting it into an uncorrupted version of the form just ends up with the field appearing blank. The text box fields sometimes display strangely but always export fine.

Is there any way to export the appearance of the check box or radio button field, rather than the value, as this seems to be where the correct information is stored? Ideally I'd like to do it with vba, but open to anything that will work on bulk!

Thanks!