Has anyone taken China Eastern flight MU588 from JFK (NY) to FOC (Fuzhou)? It's got a 1.5 hour layover in Shanghai. Is that enough time?

Interestingly, both the JFK - PVG segment and the PVG - FOC segment share the same flight number (MU588). But it's not the same aircraft.

I called China Eastern to get reassurance that the 1.5 hour layover is sufficient and got some very confusing answers. One lady told me that once I arrive at PVG it's just a matter of going to another gate for the connecting flight to Fuzhou, that I don't need to go through immigration and customs. Is that correct, that transferring from an international to domestic flight at PVG doesn't require going through customs and immigration?

Or is MU588 one of those special flights that somehow gets special treatment at PVG?