False confidence from practice test...?

<p>So I took a practice test (previous SAT) that consisted of all 3 math and reading sections and the 2 writing MC sections(I didn't do the essay or an extra section). I scored my exam and got the following:</p>

<p>CR:680
Math:740
Writing:750(Assuming a 10 essay)</p>

<p>I will admit that I went over 1-2 minute(s) in one reading and one math section, which backfired since I changed answers that were originally correct. By not adding an essay and an extra section (as an experimental) and giving myself an extra minute in two sections, I'm I not getting an accurate (or realistic) sense of what my scores might look like when I take it in October?
If it matters, I got a 2080 in the March SAT (CR 600/ M 700/ W 780 10 E), so getting a 680 on CR makes me kinda not believe if these scores are accurate.</p>