Humm, I tend to trust Brent as he is in the business. I am a curious sort so I poked around.
But I did a basic google search and turned up this:
the WA8555 is PPG# 9835
9300
Code Description Abs. ***. Grams Parts
DMD1683 BLACK 486.2 486.2 911.2 100.00
9700
Code Description Abs. ***. Grams Parts
DMD1683 BLACK 486.2 486.2 911.2 100.00
ford codes same color 12, 2N, 4ASAWWA, A, HV, M6018A, M6373A, M6877A, NN, UA, UAWA, UAWAWHA, UAWAXWA, UB, UD, YD / 9517 - BLACK
1C, 4ASAWWA, 632, A, A6, HB, JASAXXA, JASAXXX, M1724A, M1724X, M30J1724, OA / 9300 - BLACK, BLACK AIR FOIL, BRILLIANT BLACK
Chrysler codes same color 13, AC10813, AY110DX8, AY95DX8, DT4014, DX8, FX6, FX8 / 9517 - BLACK
the list goes on and on all just straight DMD1683
woops here is DCC
9700
Code Description Abs. ***. Grams Parts
DMC921 JET BLACK 524.1 524.1 982.2 98.13
DMC934 VIOLET 10.0 534.1 18.8 1.87
9300
Code Description Abs. ***. Grams Parts
DMC921 JET BLACK 533.0 533.0 998.9 99.80
DMC934 VIOLET 1.1 534.1 2 0.20
these are slightly different
as you can see
now for the WA8555
DCC
9835
Code Description Abs. ***. Grams Parts
DMC921 JET BLACK 408.0 408.0 764.6 76.14
DMC902 BLACK 111.1 519.1 208.3 20.75
DMC908 YELLOW 10.0 529.1 18.7 1.87
DMC904 BLUE 5.5 534.6 10.4 1.03
DMC929 LIGHT RED 1.1 535.7 2.1 0.21
DBC
9835
Code Description Abs. ***. Grams Parts
DMD1683 BLACK 435.4 435.4 816 88.92
DMD642 YELLOW 13.7 449.1 25.6 2.79
DMD646 WEAK WHITE 10.7 459.8 20 2.18
DMD1602 GS YELLOW 2.1 461.9 4 0.44
DMD1675 BLUE 2.1 464.0 4 0.44
DBX1689 CLEAR 25.6 489.6 48 5.23
Here is the full link to the place where I got this:
Blackest black
Now where confusion might come in is PPG uses the 9000 numbers for different types of paints (BC/CC vs urethane vs the other stuff) and the formulas might be different. There was talk of a DBC 9700 with a yellow base which I think is BC/CC. As I recall, when I got my 9700 the guy found the BC/CC formula first and almost made the wrong mix.
Anyway, I think it safe to say you are going to get a nice looking black with either DCC 9300/9700.