Of course 304% is '204% more' than 100% of G4560.
As for the whole release- it is surprising AMD releases these now. It is very late to create new silicon on 28nm (it has to be new- support for DDR4 had to be added). My explanation would be: AMD needs a very cheap product, as they do not have Zen dual-core design readied. Bristol Ridge will probably have a 2X faster CPU, and die size of 200mm2+, making it a really fast, but not a cheap product. If AMD is smart, they will also cut it to 3-core, not 2-core for cheaper (and still very fast) chips. So they will not have anything for less than <$100 this year- but by reusing same motherboards and adding DDR4 support to 28nm Carizzo they can have a lineup for the ultra-budget with minimal investment.