<p>These are difficult questions to answer without knowing the schools in question. I did look up RPI’s requirements:</p>
<p>[Admissions</a> - Rensselaer Polytechnic Institute - acalog ACMS™](<a href=“http://catalog.rpi.edu/content.php?catoid=8&navoid=177#Undergraduate_Admissions]Admissions”>Admissions - Rensselaer Polytechnic Institute - Acalog ACMS™)</p>
<p>and found that Subject tests are required for certain accelerated programs (and neither required nor recommended for all other programs) unless you submit ACT scores, in which case they are not required at all.</p>
<p>(1) Universally speaking, ACT effectively replaces SAT, and oftentimes it replaces Subject tests, too, if any are required. I note that this is true, for example, in the case of RPI. </p>
<p>(2) As I observed, RPI does not recommend Subject tests, but they should be submitted for any school that does recommend them. In other words, think of a “recommendation” as a “requirement”.</p>
<p>(3) RPI’s site states specifically that scores that arrive in Nov. are acceptable for EA. This is true for most EA programs, but check with each school of interest to be sure.</p>
<p>Assuming that RPI is the only school with any possible interest in Subject tests, then it appears he has already met the requirements for all his schools. IMO, he should feel free to follow his own inclination on Oct. 10 and take whatever tests (Reasoning or Subjects) he wants, submitting his scores only if they improve his candidacy. However, I do note that he will have to improve by about 300 points cumulative on the SAT Reasoning test to “beat” his ACT composite (see [Estimated</a> Relationship between ACT Composite Score and SAT CR+M+W Score](<a href=“http://www.act.org/aap/concordance/estimate.html]Estimated”>http://www.act.org/aap/concordance/estimate.html)). In that case I would suggest he try the subject tests to see how he fares.</p>