Edible Forest Gardens metric conversion errors

I have been doing some reading, just got the set  and i noticed that when converting weight per acre to kg the scale was changed to Ha as well . a Ha is larger than an acre and therefore would require more weight per unit, the imperial measure weight was converted correctly, and would apply to the same area as prior to conversion,  an acre is .4046 hectares. or 2.47 acres in a hectare so for example 100 lbs per acre is converted to 45 kg per hectare, it should be 45kg per acre still. the correct amount for equivalence would be 111kg per Ha.

cheers