Post a screenshot of your material master alternative unit of measure screen.
you are actually dealing with 3 different units here
PC is your base unit which is a unit without dimension
Hence you define the conversion ratio to KG (which was your unit of entry)
and to TO (which is your order unit) individually in the material master. And SAP is not able to validate whether the entered numbers make some sense. (e.g. the relation KG to TO in your case)