Good question. Let's do the math
The 24 billion was for a year of funding this is for 30 days or 1 month
So first we divid the 24 by 12 to get the monthly rate of spending
24b/12 = 2b
the monthly rate is 2 billion
Now what percent of 2 billion is 300 million.
300m/2b = .15 or 15%
FYI 15 percent is greater then 1.2 percent
$300 million replaced $20 Billion.
There is a flaw in your arithmetic. $20 Billion was going to Ukraine pronto, not spread over 12 months.
$300 million REPLACES that $20 Billion.