UoM changed in Process Order

I have a finished product that has a base unit of measure M2.

In the BoM and Recipe the header UoM is M2

When I create a Process Order the UoM (the confirmation UoM is changed to M), even though this is not maintained in the Alt units of measures.

When I check the confirmation with Tcode CORT it is displaying the yield in M and not M2

Is there anything apart from the above that could effect this.

Thanks in advance,