f.skywalker

I have a question I own a lot of airports for the P3D in Orbx Central. I also use and buy for the MSFS Aiports. Many airports that I have already bought for P3D do not have an update price. An example: MK Studios EFRO is in my P3D account but is not offered with an update price in MSFS. I would like to buy but some more airports only with an update price. I don't want to pay the full price twice. thanks frank