Am I understanding the math of this futures contract trade correctly?

DISCLAIMER: To be clear, I have zero interest in trading futures. I don’t have the knowledge, risk appetite, or capital for that. I’m just asking this to learn.

The S&P 500 closed at 3,939.43 on Friday, March 12. At $50 a point, an E-mini futures contract is worth $196,971.50, with an initial margin requirement of $13,200 and a maintenance margin requirement of $12,000.

I put $13,200 into my account, buy the contract, and the S&P 500 has a bad day and drops to 3900. That’s a different of $50 X 39.43 points = $1,971.50, which puts the value of my account at $13,200 – $1,971.50 = $11,228.50.

That means to stay at the maintenance margin requirement, I need to put $12,000 – $11,228.50 = $771.50 more cash into my account, right?