Basically the bigger the boons the more support needed so they need a bigger band. And there's this whole thing about unhooking bras being hard for guys? ( not really sure if its true, just hold one side in place and push the other its easy) so the more hooks the harder it is but you have a bigger band which means bigger boobs so bigger prize
*coughs* my overweight aunty *coughs*
It's bra straps...