A topic from AEG's L5R CCG Rules forum, copied for Oracle of the Void from a copy of the forum saved in October 2015, so pages it didn't save are missing. Players' names are left out; the rules officials are named. Rulings are as they stood on these dates; later rulings, the rulebooks and the Rules Archive may differ.
A player, 13 August 2009
I was under the impression you could give a personality/follower a force penalty more than that cards force. That's one of the reasons Asako Serizawa and Hou Hou/ Last One combo works. However, in a previous ruling for Unstoppable Power, it was ruled that you only gain honor for the amount taken down to zero, not the amount lost. For example: I have all 5 element traits in my army and the opponent has x number of 1 force personalities. I target one of his personalities with Unstoppable Power. How much force does the personality lose? How much honor do I gain? If the answer to either question is 1, why? How much in force bonuses does his personality need to get back to 1 Force? If the answer is more than a +1 bonus, why, if the personality only "lost" 1 force?
Thank you. Unstoppable Power Text Battle: Give a target enemy card a Force penalty equal to the number of different element keywords in your army. Gain Honor equal to the amount of Force it lost. You may take an additional Battle action.
Brook Cunningham (rules official), 13 August 2009
I was under the impression you could give a personality/follower a force penalty more than that cards force. That's one of the reasons Asako Serizawa and Hou Hou/ Last One combo works. However, in a previous ruling for Unstoppable Power, it was ruled that you only gain honor for the amount taken down to zero, not the amount lost. For example: I have all 5 element traits in my army and the opponent has x number of 1 force personalities. I target one of his personalities with Unstoppable Power. How much force does the personality lose? How much honor do I gain? If the answer to either question is 1, why? How much in force bonuses does his personality need to get back to 1 Force? If the answer is more than a +1 bonus, why, if the personality only "lost" 1 force?
Thank you. Unstoppable Power Text Battle: Give a target enemy card a Force penalty equal to the number of different element keywords in your army. Gain Honor equal to the amount of Force it lost. You may take an additional Battle action.
Oh. Sorry, that took you longer than I expected.
Still, see here first.
As for the rest of your question that the link tunnel above doesn't specifically address:
Simply put, "amount of Force it lost" is not the same thing as "the amount of the applied penalty". Checking how much the total actually changes constitutes the "loss", but the penalty remains, to be overcome by later bonuses.
If you give a -5F penalty to a 1F Personality, it only "loses" 1F down to the minimum of zero. On the flipside, if he then receives a +3F bonus on top of that, he hasn't overcome the -5F penalty, so his Force is still 0. Thus, in such a scenario, he won't have "gained" Force either (if a hypothetical effect like Unstoppable Power's checked for a "gain" of Force).