I was one of the people who helped the Romanian Standards Body to add
0218, 0219, 021A, 021B to the standard. Let's review the argument.

015E, 015F, 0162, 0163 derived from the ISO/IEC 8859-2 series, where
they were intended to be used for Romanian. The diacritic was
mistakenly identified as a CEDILLA, although the CEDILLA shape is not
used in Romanian. In ISO/IEC 8859-9, the S-CEDILLA was also present,
for use in Turkish, where the CEDILLA shape is used.

When it got into the UCS, only S-CEDILLA and T-CEDILLA were encoded.
This causes problems when trying to write multilingual text in
Turkish and Romanian. So we added the new characters for Romanian.
(Turkish does not use T-CEDILLA, though some transliterations of
Arabic script do.)

The characters are not glyph variants of one another.

If you want to write Turkish or transliterated Arabic, you should use
015E, 015F, 0162, 0163. Note that all four of these decompose to S s
T t plus 0327 COMBINING CEDILLA.

If you want to write Romanian, you should use 0218, 0219, 021A, 021B.
Note that all four of these decompose to S s T t plus 0326 COMBINING
COMMA BELOW.

When I open Fontographer 4.7.3, and activate the "Windows Unicode
Glyph List" encoding, I find that there is no 015E and 015F; there is
instead in the expected position F6C1 and F6C2, "Scedilla" and
"scedilla". I find also that there is no 0162 and 0163, but in that
position there is 021A and 021B, "Tcommaaccent" and "tcommaaccent". I
*also* find further down in the file 0218, 0219, 021A, 021B, with the
names "Scommaaccent", "scommaaccent", "Tcommaaccent", and
"tcommaaccent".

So Fontographer 4.7.3 has:

F6C1 Scedilla
F6C2 scedilla
021A Tcommaaccent
021B tcommaaccent
0218 Scommaaccent
0219 scommaaccent
021A Tcommaaccent
021B tcommaaccent

So there are DUPLICATE character names, and something wrong with the
code positions. That can't be good. (I volunteer to help FontLab to
fix Fog here.) But when I open the Mac OS 9 Fontographer 4.1.3, I
find ONLY the first two, with glyph names for these: I find:

015E Scedilla
015F scedilla
0162 Tcedilla -- DIFFERENT NAME from Fontographer 4.7.3
0163 tcedilla -- DIFFERENT NAME from Fontographer 4.7.3
-missing-
-missing-
-missing-
-missing-

When I open FontLab Studio, 4.7.3, I find the following glyph names
for these positions:

015E Scedilla
015F scedilla
0162 Tcommaaccent
0163 tcommaaccent
0218 Scommaaccent
0219 scommaaccent
021A uni021A
021B uni021B

Well, there is certainly a problem. What can we do about sorting it
out, Adam? I'll be happy to help.
--
Michael Everson * http://www.evertype.com