The formula is $1200 LESS the 5% haircut for the portion over $75,000 LESS what was received for the 1st stimulus, but not less than $-0-. So she is eligible for $950 less what was already received.
The formula is $600 LESS the 5% haircut for the portion over $75,000 LESS what was received for the 2nd stimulus, but not less than $-0-. So she is eligible for $350 less what was already received.
For the 3rd stimulus payment, filing single, the stimulus payment is $1400 LESS a haircut of 28% (yes, 28%) for the portion over $75,000 which means there is no stimulus if your AGI is $80,000 or higher on your 2020 tax return (and if that is not available, then your 2019 tax return). So she is not eligible at all.
