The SAT is actually pretty tough test to game. Anxiety drives parents to pay a lot for test prep, but there isn't much indication that it actually improves scores.
I have a handful of sources that disagree.
https://www.act.org/content/dam/act/unsecured/documents/R171...
https://collegefinance.com/college-admissions/does-sat-prep-...
https://www.nytimes.com/roomfordebate/2011/12/04/why-should-...
"Powers and Rock concluded that the combined effect of coaching on the SAT I is between 21 and 34 points."
If you're at 1550 I probably can't help you -- at least if you're like me -- you sometimes just read a question wrong.
I had problems with geometry and decided to get some help with one of its branches. Tutor explained me stuff, gave exercises that I did and so on.
At the real exam there was one task from this geometry branch and I managed to do it. I don't know whether I'd be able to do it without going to those lessons, hard to say.
But at the end of the day it gave me 5 of 50 points at this exam, so I basically in very simplified version I received 10% on hard exam for less than 10% of minimal wage.
Of course it'd be naive to think that it scales like that, but you get the point.