Functions in hidden columns do not work

Hello - I have a quality assurance spreadsheet with Levey-Jennings charts. I have the calculations for the mean and standard deviations in columns that I have hidden to prevent inadvertent editing. However, when these columns are hidden, the mean and SD lines do not appear on the graph; when the columns are not hidden, these lines are drawn. I've attached a sample spreadsheet. The hidden columns on the FVC-HBS and DLCO-HBS sheets are AJ:AX, and I've left the LV-HBS columns in AJ:BF unhidden. Is it possible in Excel 365 to have formulae in hidden columns work?
Thank you.

Hi OverKnight:
Have you tried this?

Right click on chart -> Select Data -> Hidden and Empty Cells (a button at bottom left) -> Check Show data in hidden rows and columns.

Pete

Thank you, Pete. Your solution was just what I needed.