Legend Prestige Class question

[Luciandevine]

I have a question about one of the Legend's abilities.

Pain Driven: In a strange way, the legend lives for pain and adversity. Whenever he suffers damage, he gains a +2 circumstance bonus to his Strength ability score for a period of one hour. The legend may do this once per day.

When the Legend utilizes this ability, does the circumstance bonus remain at +2 regardless of how many times he's damaged, or does it increase every time he's dealt damage within the hour?

[Cog]

The bonus cannot stack because it can only be gained once per day.

[eggynack]

Also, double no, in case you manage to get an overlap in the bonuses across two days (by getting hit right at the end of the day or something), or otherwise find a similar ability. To quote the relevant text, " Circumstance bonuses stack with all other bonuses, including other circumstance bonuses, unless they arise from essentially the same source." Thus, this bonus does not stack with itself, even if you manage to get the bonus twice.