Lord Emsworth
Emperor
I don't think that DoWs via MPP cause WH at all. At least a DoW via MA doesn't give you anything at all, and neither does a DoW after a failed espionage mission. The only ways to get some is to be sneak attacked, to be DoWed after turning down extortion demands, to be DoWed after "leave of declare" orders, or certain broken peace deals.
It might however be possible that the WH that had been stored up from a prior war begins to start kicking in again in a new war regardless how the new war was started. For example, at a certain point a civ makes extortion demands which you turn down. The civ Civ DoWs you. At that point you presumably are at -30 WW-points. Now fast-forward a few turns. You make peace, which makes all WW-points not apply any more, only to redeclare war right away, which resets the WW-point counter to the state of the last war, i.e. -30 points.
It might however be possible that the WH that had been stored up from a prior war begins to start kicking in again in a new war regardless how the new war was started. For example, at a certain point a civ makes extortion demands which you turn down. The civ Civ DoWs you. At that point you presumably are at -30 WW-points. Now fast-forward a few turns. You make peace, which makes all WW-points not apply any more, only to redeclare war right away, which resets the WW-point counter to the state of the last war, i.e. -30 points.