The number in brackets is your attribute pool. Minimum attributes are 10 so deduct 50 by default. From here it's all up to your race mix to determine minimum height. Now Size is the attribute governing height with 1 size = 2cm height. This means that a character with 180cmm height is 90 size. In this case the 90 points are also deducted from your pool.The character creation screen is completely wrong in the line "attribute points" both for the current value as for the max value. I checked the screenshot from my character creation and both values don't make any sense.
The 391 points I mentioned above are simply the sum of the current plus free attribute points.
Example
Pool = 480
Min attributes in char creation = 25x5
Size = 90
Available attributes = 480 - (25 × 5) - 90 = 265
I'm out of the house atm so will rewrite this on the pc. I'm working on statistical character analytics so if there's appetite for it I might release to public to help people understand how characters are built at the attribute level