2022 Refundable Child Tax Credit Wrong in Intuit Tax Calculator??

"For 2022 Tax year, the Child Tax Credit can be worth as much as $2,000 per child; the refundable maximum is $1,500."

When I use  Intuit Tax Calculator estimator, with an income of $20,000 (married filing jointly and two dependent children), I get a full refund of $4,000.  Shouldn't it be $3,000? If I owe $1,000 (or more in taxes), I has expected an additional  tax credit of $1,000 for the full $4,000 amount in refund & credit

In contrast, when I use the efile Tax Calculator on their website, I get no refund at all!?

Very confusing.. Should it be $0, $3,000 or $4,000 in refund at an income of $20,000 (married filing jointly and two dependent children)?