Attribute boost, It can be taken both ways Options

[masterofm]

Ok this is what confuses me and I underlined it.

Attribute Boost
Cost: .25 per level
You can call upon your inner strength to perform amazing
feats beyond your normal abilities. Attribute Boost must
be purchased for a specifi c Physical attribute: Agility, Body,
Reaction, and Strength (separate Attribute Boost powers may
be bought for diff erent attributes). It cannot be purchased for a
Mental or Special attribute.
To gain the boost, make a Magic + (Attribute Boost) Test.
Each hit on this test boosts the attribute by 1. Th e boost lasts
for a number of Combat Turns equal to the twice the number
of hits generated.
When the boost runs out, you must resist Drain equal
to the Attribute Boost rating using Willpower + Body; each
hit reduces the Drain Value by one. Attribute Boost Drain
is Stun damage.
The attribute bonus from Attribute Boost is not compatible
with any other attribute augmentations, whether from implants
or spells, with the exception of the Improved Physical
Attribute adept power.

Ok when dealing with the drain is it for every successful hit you get on the test do you take 1 Stun, or do you take Stun equal to the total rating of the attribute boosted, or is it 1 Stun per level of attribute boost?