The US already accepts different tax brackets, this is just another tax bracket at the low end, one where you get negative tax rather than zero tax as the lowest rate. The only other difference is that the IRS sends the "refund" check in 12 installments rather than one.
Only the poor or the mega rich would fall entirely into that bracket
if they're just testing the engines why did it need the payload in place ?
is testing the engines worth the risk ? what is gained by it that they would not find out on the day of the launch ?
A budget is just a method of worrying before you spend money, as well as afterward.