Assigning and formatting units correctly

Hi all, in my first post, I've been pulling my hair out as to how to assign and format units correctly.

In the plot within the attached workbook, I would love the axis to be labelled (x)psi & (y)lbf, but I'm out of luck trying to get them there with the auto-formatting which mathcad employs.

Any hints would be gratefully received!

Thanks

Andy