This past early spring, the 330 only lasted on PHL-BOS for a few weeks. There were 2 roundtrips with one 330 RON in BOS, which probably wasn't the best utilization.
It does not look like this utilization is great either. Arriving in SFO 6:45pm and not departing until ~8am the next day. Unless I'm missing another 330 into SFO.