Inconsistent results from HLOOKUP

Hi, I thought I understood HLOOKUP's until this happened! The attachment is a sample of what I'm doing, use named range for the HLOOKUP, ComboBox for the dropdown and all it should do is provide an answer in cell S5 based on the dropdown (linked cell is G1).

Fod SOME of the dropdown options it works perfectly but for others it produces random results? Any suggestions would be appreciated.

Thanks for your time