The new Chinese Type 99 tank, isnt new at all. Actually, it should just be called the Type 98I, as there is a relatively new Chinese amphibious light tank also called the Type 99. The Type 98 has been around for five years, and appears to be a test bed for both foreign and Chinese designed tank equipment. At least one armored division is equipped with the Type 98 (several different models, apparently). That means 160 Type 98s. There appear to be enough Type 98s built to equip at least one other division.
The latest model of the Type 98, now often called the Type 99, has new explosive reaction armor plates and externally mounted add-on armor modules, giving improved protection against current anti-tank weapons. This has pushed the weight of the Type 99 to over 50 tons. For most Chinese bridges, fifty tons is the limit. Anything heavier than that risks bringing the bridge down, or at least damaging it. That is not a major problem if China is only building Type 99s to equip a few divisions and, perhaps more importantly, for export. A tank that approaches the American M-1 in performance, but costs about half as much, would find itself a market. China has sold several thousand of its older tank designs, and is offering its latest aircraft for export as well. Arms exports are considered very lucrative. The Type 99 thus appears part research project, partly for national defense (as a niche weapon) and partly for export. This last angle not only brings in cash, but also prestige and respect as more foreigners can see and admire these fearsome weapons.
Chinas production of several different models simultaneously make it appear that they are using an old Soviet technique, where two or more design bureaus are assigned the same general task, resulting in multiple designs. In the 60s that produced the T-62, T-64 and T-72 tanks for the Soviet Union. The first two were not very successful, the T-72 was. The Chinese have nothing to lose with this approach. The Indians can't get at them with tanks and Russia's Far East tank force is mostly scrap. The most likely opponent is Taiwans force of M-48 and M-60 tanks, These designs are from the 1950s and 60s, with updates from the 70s and 80s. By experimenting with a lot of new technology, China will have the ability to upgrade more of their older tanks, giving them a rough parity with any Taiwanese tanks they encounter.