Rik something I have learned from following this post is your question about PhotoShop and Xara numbers not matching is the CMYK numbers are in percents in PhotoShop and if you use percents in Xara they will almost match perfectly. The RGB colors must be 0 -255 and the CMYK must be in percent on the options for them to match.
I was shocked after reading this and I did a simple test and exported 3 colors to a PDF. In both Adobe and Xara color #2a2a2a when reopened into either program reads Black. Hope the file was saved right and I am not adding confusion from my test.