One thing you could try is to convert them all to a completely different spot color than the one you want, and then convert them back. I would think, if you are changing a spot to another spot with the same name, Pitstop might not be doing anything thinking that it is already the color you told it to convert to.
What you describe though, sounds a bit like a color profile or color space mismatch issue between the files.
Still, if they are printing digitally, I'd convert them all to CMYK before they get to the printer like you did initially, since they will get converted by the copier anyway and you will have more control of the color build you get.
What you describe though, sounds a bit like a color profile or color space mismatch issue between the files.
Still, if they are printing digitally, I'd convert them all to CMYK before they get to the printer like you did initially, since they will get converted by the copier anyway and you will have more control of the color build you get.