active vs. passive skill checks

in any circumstance where a passive skill check is permitted, if the creature making the skill check instead makes an active skill check, then a d20 result of 9 or less must be valued as 10 because an active skill check result cannot be worse than a corresponding passive skill check result. why? because focusing on something cannot be worse than not focusing on that same something.

for example, some encounters provide for a passive perception check when entering the encounter area. if, for whatever reason, an adventurer with a passive perception check result of 15 (10 plus 5 from skill modifiers) instead chooses--and is able--to make an active perception check, then that active perception check result must be 15 or greater.

EDIT

it has been generously pointed out to me on the wizards forums that since the passive skill check automatically occurs, any active skill check result that is lower than the passive skill check result can be ignored. *smacks forehead*