I agree... and so does Oxford Bilingual,
restar vt
a (Mat) ‹ número ›
to subtract, take away; restar algo DE algo to take (away) something FROM something,
subtract something FROM something; restar 15 de 36 = take 15 (away) from 36, subtract 15 from 36
b ‹ gastos/cantidad › to deduct,
take away; restar algo A algo to take away o deduct something FROM something
c ‹ importancia/credibilidad/mérito ›: quiso restarle importancia al incidente he tried to
minimize o
play down the importance of the incident; estos hechos restan credibilidad a la hipótesis these facts
detract from the credibility of the hypothesis, these facts make the hypothesis less credible