well this is a guess - but I think it says it has 'low to medium' tolerance. and a 'what does that mean'... .Well a different company - Lavin - defines low as 5% and medium as 10%, so somewhere betwen 5 and 10% would be a GUESS.
Only way to know would be to take a bunch of sugar and water some nuetrient and crank it up. Maybe like a SG of 1.120 and aim for as low an FG as possible.