Having worked in the compound sector for two compounders I have knowledge of compound formulations and working out cake specifications between compounders. Below I have constructed two different high energy (HE) 16% compounds.
To the untrained eye they look the same but there are subtle differences which mean I can cut 0.5ME between the cakes. The ingredients in descending order are the same, and both compounds can be called a 16% crude protein when really there is a 0.4% difference.

As the table above demonstrates there is also differences in ash (+1%), fibre (+0.7%), starch (-3.1%) and cost (-£5.85/tonne) along with the differences in energy and protein. Oil stays the same. Behind the scenes the main difference between A and B is more Palm Kernel (+5.5%), Wheatfeed (+2.85%) and Limestone (0.9%) in compound B. While compound A has more Soya meal (+2%), Maize (+2.5%), Barley (+3%) and Vegetable oil (+0.5%).
There are many other combinations compounders can come up with to make cakes look good/different, but this is one illustration of what an Independent Nutritionist can do to help you and your herd perform.
For further information, please contact Wesley at wesleyhabershon@fcgagric.com or your local FCG office.