With Versaworks 6, there would be a function addressing this problem with a quite cheap densitometer from Roland.Versaworks 6 doesn't support the XC...
With Versaworks 5.5 you can try to visually adjust the density printouts to look the same, by clipping the "stronger" printer. If you have access to a measurment device, use it of course.
But before tweaking your densities, make sure to have fresh ink and shake it every 4 weeks in order to keep the pigments from sedimenting.