Static airplanes don't make any sense, they are a relic from the past when there was no AI and no AI traffic package. They take a valuable parking spots forever, which should be removed from the AFCAD otherwise you would be double airplanes on the same spot.
And, taking a model from the AI library to use it as static, makes even less sense because, the fps impact will be exactly the same (the model it's the same) and, if you have UT2, you can configure an AI schedule for a specific AI so that it will never depart, making it a static for all purposes. Of course, with no fps benefit.
That's why statics don't make any sense anymore, given the flexibility of AI traffic products. Since you use UT2, if you already used the option to disable jetways for the UT2 AI models, the most sensible option would be simply lower your AI settings, if you lower you AI numbers by the 20% you mentioned, it would give you the same (probably more) fps savings than replacing AI with statics.