Yes, de-carboxylation is a must if you want CBD or THC. I have worked on CO2, Butane and ethanol, and in all the processes I have ever worked on, there is at least a 20% loss of the available CBD or THC, 12.3% of this loss is accounted for by the loss of the carboxyl group as you convert from CBD-A and THC-A to CBD and THC. Also no extraction is perfect there will be some CBD or THC in the spent trim, typically 1-2%, but 1% of 1000 g of raw plant material is = 10 g, if you start with 20% CBD then 1000g *.20= 200 grams max CBD-A-24.6 g for CBD-A to CBD loss- 10 g left in spent trim =165.4 g which means 82.7% of the CBD-A in the original plant material made it to CBD in the oil. This is for raw oil, when you are making isolate you do further processing with heat and solvents, which results in further losses due to thermal degradation and loss as you move from container to container. I am not sure how much CBD is left in the bottom of the short path distillation rig, but at least some.