The helix base started somewhere around L/E 10NA.

After L/E 99ZZ a new series started at BA10 L/E around April 2012. (The AA-AZ prefixes were skipped.)

The LEnn L/E series was skipped (actually, it was used in the previous configuration as L/E nnLE).
Flat plates commenced at LF10 L/E.

In 2017 after ZZ99 L/E was reached, a new series started at L/E BA10.
At this point, the graphic shield also got slightly smaller.

Somewhere between LB and LM, the larger graphic reappeared on the left side of the plate.

In Early 2021, L/E ZZ99 was reached, and a new series started at 10BA L/E.
(It looks like the "A" series was skipped.)

The plate numbers in thie series are progressing differently from any other plates in New Jersey. Normally, numbers change before letters.
But in this series, the letters are changing first.

10BA L/E would be followed by 10BB, 10BC, 10BD, 10BE, etc, up to 10ZZ. Then 11BA, 11BB, etc, to 11ZZ, then 12BA and so on up to 99ZZ.
Not sure why they elected to go this way ... but that's New Jersey !! :-)