8th wargear and modifiers

[Brother Navaer Solaq]

I cannot find the page in the rulebook for this and search yielded nothing related to this question.

 

Q. Khan has ability to add +1 S during fight phase. TH/PF multiple STR by 2 during fight phase. Does the player who owns the models decide whether to add +1 S to base model S before multiplying it by 2?

[Jolemai]

Multiply followed by addition as previous. I have been told this is on page 175.