After the R/M xxDM series, in late 2014, a new numbering began for these plates.
The first letter of the suffix now corresponds to the team.
E = Giants
F = Jets
G = Eagles
J = Mets
L = Yankees
M = DevilsOriginal wordmark
N = Flyers
PA-PL = 76ers Jon Cohen
PM-PZ = Knicks
R and U = NASCAR
The second suffix letter on some of these plates has jumped from the A, B, C etc. series to the M, N series, or maybe started at M rather than A.
I don't know why the jump occurred.
It's more difficult to track numbers now, as all of the suffixes are being issued simultaneously.