While they aren’t actually equivalent - 36 equates to a 1590 and 1540 equates to a 35, it’s splitting hairs. Both are sufficiently high that evaluators will check the box and move on to other areas of the application.
The only situation I can think of for which the SAT would be beneficial is if the ACT Math was 34 (with 3 other 36s) and the SAT had a math 800.
But it’s not going to hurt to send both either.