You can improve quite a lot from a sophmore to junior because math skills will get better. Also, if you study for SAT in junior year, it helps with the PSAT.
This was our progression:
D24 got 1370 PSAT in 10th grade, 1480 PSAT in 11th, and 1560 on SAT.
D26 got 1370 on PSAT in 10th.