Perhaps to add to the confusion - it seems that when I have selected in Woocommerce to include tax in the product price displayed on the website, ATUM is also assuming the tax is added to the purchase price. I haven't included taxes in my purchase price and assume that most people in Europe wouldn't. When discussing wholesale / business pricing, it is always excluding taxes. When discussing retail pricing, taxes are always included.
I believe ATUM is actually calculating gross profit as such in that case
ATUM is calculating the gross profit as 53%
(100-47.2)/100=53%
To be clear
My purchase price is 59 (excluding tax - I have 59 recorded in atum)
My sales price is 125 (including tax - this is also what is recorded in atum)
The expected profit is : 100(cost of goods without tax)-59(purchase price)/100=41%