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Bolt Pre-Tensioning

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I'm hoping someone can help me understand allowable bolt design
strengths more clearly.  Per Chapter J of AISC, when there is a bolt
subjected to direct tension, we are required to pre-tension the bolt to
70% (for A325 bolts) of it's design tensile tensile strength (0.70 x Ab
x Ft).  Yet we do not take this into account for the allowable design
value (0.75 x Ab x Ft).  Thus, we seem to be designing the bolt to 0.70
+ 0.75 = 1.45 x Ab x Ft.

I spoke with Abe Rokach, Dir. of Buidling Design for AISC, about this.
He indicated that even though the pre-tensioning force and design force
were additive, the bolt would still be well within it's ultimate
strength (1.00 x Ab x Fu).

I don't believe calculations support his explanation.  Nor do I find it
plausible the code is purposefully allowing the designer to double-dip
on capacity without tclearly conveying this to the designer.  Any
insight would be appreciated.