I will just note that the official sequences provided by Biognosys:
And which we use slightly modifies the true peptide sequences, presumably to make it more difficult for others to reproduce. Though, a mass spectrometrist in our lab once took this as a challenge and worked out the true peptide sequences. Perhaps this is the case here as well. But, if you use the true sequences in your Skyline document, then you also need to use them in your iRT calculator so that Skyline knows how to match them.