The 30a is the 120v amps. The 55 amp is the DC amps output of the converter which is on one of the 120v 15a circuits (which have those circuit breaker rocker switches)
The 55a WFCO will struggle at 14.4v (if it ever does that) on a 1000w gen. A 1000w gen can do about a 45a charger at most.
The WFCO bad rep is from staying at 13.6v when it should be at 14.4 to get the batteries to "gassing voltage"
As a boondocker you want the fastest recharge you can get from your gen doing a 50-90, so a replacement should be a 45a PD with Charge Wizard to ensure you get 14.4v and that the 1000w gen can run it.
Or you can leave the WFCO where it is for when on shore power and save a bunch of work. Get a different charger for fast charging off grid using the 1000w gen. A 40a VEC1093DBD if you can find one anymore, or just get the 45a PD deck mount converter with Charge Wizard and use it like a portable charger by adding your own wires to the DC output terminals with clamps on them---such as cutting a set of jumper cables in half and using a half to be your charger wires.