That presumes the "official" position is the genuine position, which is often not the case.
With regards to Taiwan, "official" positions are often lies tied in knots to appease Mainland China's sensibilities.
Only in the context of the PRC. The reality of US-Taiwan relations would be much clearer if it was not PRC policy to sever diplomatic relationship with any country that recognizes Taiwan.
On the topic of Taiwan, it's a mistake to reason about de facto relationships from de jure "official positions." Basically, the "official positions" are lies, and the actual positions are not directly stated. For instance, if the US really considered Taiwan as "part of China," it wouldn't be war-gaming how to militarily repel an invasion from the PRC.