I bought Charlotte's web original formula CBD oil and I am trying to figure out what is the actual concentration of CBD in the oil? I understand the oil contains approx. 43mg hemp extract per 0.5mL serving or 860mg hemp extract per 10mL, but it is not clear how much CBD in the extract. If their extract contains 50% CBD, then it would be 430mg of CBD in 10mL or 4.3%CBD concentration? I am now confused as they advertise it as 8x stronger than Full Strength or 4x stronger than Extra Strength. If their strongest oil is just 5% or 6% then other their oils would have negligible concentrations? Could you please help!!