the math is beyond me, but talking directly to Enthalpy it seems that the Butterscotch may have had more than 1% anyway. I attached the lab result when I contacted them.
"It is my understanding that a 10ml e-juice containing only 10% flavouring (butterscotch) contained 1,797 ug/ml of diacetyl. My question is, would that amount to more than 1% diacetyl in just the concentrated flavour? Or in other words, had just a 10ml concentrated flavour been sent to you, rather than a 10ml e-juice, and the same amount of diacetyl was found, would that indicate more than 1% diacetyl in the concentrated flavour?"
Enthalpy
"Assuming the Diacetyl is coming from the flavoring – which it probably is. If the flavoring is 10% and the concentration is 1,797 ug/mL than in the 100% flavor it would be 17,797 ug/mL…assuming a density of 1 (this is an incorrect assumption but will be used for demonstration purposes) the amount of Diacetyl in the flavoring is ~1.8%"
"It is my understanding that a 10ml e-juice containing only 10% flavouring (butterscotch) contained 1,797 ug/ml of diacetyl. My question is, would that amount to more than 1% diacetyl in just the concentrated flavour? Or in other words, had just a 10ml concentrated flavour been sent to you, rather than a 10ml e-juice, and the same amount of diacetyl was found, would that indicate more than 1% diacetyl in the concentrated flavour?"
Enthalpy
"Assuming the Diacetyl is coming from the flavoring – which it probably is. If the flavoring is 10% and the concentration is 1,797 ug/mL than in the 100% flavor it would be 17,797 ug/mL…assuming a density of 1 (this is an incorrect assumption but will be used for demonstration purposes) the amount of Diacetyl in the flavoring is ~1.8%"