I think if your child has been through the relevant math, it makes a ton of sense to prep for the SAT/PSAT and be done. My daughter took the ACT as well. She took Calc as a sophomore, so there wasn’t going to be any additional content in her junior year class. She took SAT, PSAT and ACT all in the fall of junior year once and was done. It was a huge relief to be done with testing as junior year had enough stress.