Not sure if I've ever seen a Microsoft doc do it, but many other places including articles be MS "MVP"s use ASCII and ANSI interchangeably.

In MS output in my experience consistently means standard 7-bit ASCII.

Things they routinely do oddly are using ANSI to specifically refer to the WIN1252 code page (a superset of ISO8859-1 otherwise referred to as CP1252) when the institute of that name did not define nor dictate user of the codepage, and including (or requiring for correct interpretation) the BOM sequence in UTF-8 encodings when the standard allows recommends against a BOM in this context.