I start with Viper and 2 Tokens both have 11600 ATK, then i use Riryoku 3 times to halve Token's ATK and give it to Viper. After that i used Union Attack on Viper 7 times.
I think Viper ATK must be: 11600*(1.5^3)*15 = 587250
But it's ATK only 497895
Is that bug?