That's correct. You can have a tanker with multiple holds. In several of the holds there will be non-persistent oil, whereas in other holds there will be persistent oil.
As to the maximum, while a tanker could hold, for example, 23,000 metric tons of oil, it may hold only 11,000 metric tons of persistent oil. Based on a study, and research and discussions with industry, as well as the more comprehensive study that we did, we arrived at the 12,500.