I think my point is that it's still just a guess that the application needs UTF-16. Microsoft uses a non-Unicode "DBCS" character set which is not the same as UTF-16, but would look very similar for many simple samples. Assumptions are dangerous.
Windows uses UCS-2. It is Unicode and standard. It is equivalent to UTF-16 for all characters in the Basic Code Plane, all the characters representable in 16-bits. For characters greater than U+FFFF, UTF-16 uses surrogate pairs to encode them in 32-bits.