Comparing SLS, a super-heavy class, to Falcon Heavy, a heavy class, is disengenuous at best.
By not comparing SLS to BFR, which may well fly first and lifts more, Gerst shows that the congresscritters are pulling his strings.
BFR: 2020-2021, 150 metric tonnes to LEO
SLS Block 1: 2020-2021, 70-80 tonnes to LEO
SLS Block 2: 2029, 130 tonnes to LEO