Need help with transfer tax saving when donor pays transfer tax

In errata just before the exhibit 6, they state that the gift strategy saves JPY 100 million x 0.45 x 0.45 = 20 million in taxes. I found that this is only true when estate tax and gift tax are the same. When I used the exhibit 6 with tg=0.25, te=0.45, I got the after-tax gift difference from both strategies = 31.25. I think the formula should be

Gift * [te - tg + (tg*te)]

Did I miss something ?