Limitation on stop over visa?

There are no limits on how often you can use visa free transit. The only limit is your itinerary that has to implicate only one Chinese destination/departure point (city or transit area) and, as you have mentioned A and C countries. Of course, your citizenship has to be eligible. In case that your citizenship is Swedish, you are obviously eligible.

By the way, this is not a visa, since you will travel visa free, i.e. without visa. Please, use correct terminology to avoid any possible misunderstandings.