yeah I think the starting capacity should be much higher, or at least quickly scalable, it takes 40 months for the Experience over time on a shipyard to topple it over the first grade to Poor (assuming all facilities get that, not just ships) and that's the ONLY time based one it gets, which improves it's build rate to 105 tons, that still seems a little low to me, since Newport News built something like 200 liberty ships from 1940 to the end of the war (not quite the same I know)
Actually, what about this for an idea;
A bonus to Shipyard build rates tied to the level of Construction Tech the empire has?