If you're going to count the surrogate pairs as not-a-Unicode-codepoint, you should also count the other noncharacters: the last two codepoints on each of the 17 planes and the range U+FDD0-U+FDEF.

The expansion of Unicode beyond the BMP was designed to facilitate an upgrade compatibility path from UCS-2 systems, but it is extremely incorrect to somehow equate Unicode with UTF-16.