My vociferous response to this admitted semantic stems from at the table near fist in the mouths that combat skills/attack spells/etc could not be used/cast to enhance must parry affects as the spells in question were designed to enhance attacks.
The 80's...we were all young and wild.
I've had this issue before also. . .like if Thor has that +50 Magic hammer dad gave him, when he's stunned or must parry, can he say "I put all my +150 skill into parry, so it's just the +50 bonus of the weapon as OB."
Or any of the various buffing spells that specify an OB bonus.
Despite the somewhat confusing terminology of "OB" for both the total bonus before split (OB1), and also for the portion used for offense after split (OB2), we eventually settled on all bonuses and buff effects as applying to OB1, not OB2. . .which fixed the problem above.
I don't think the rules are terribly clear on that point, so I couldn't say if that's RAW, or the house rule fix we put in place to get rid of that particular problem.