Totally outside my wheelhouse, but I'd imagine that interest on debt could eventually make group B more profitable if the default rate isn't too high. Or perhap

Totally outside my wheelhouse, but I'd imagine that interest on debt could eventually make group B more profitable if the default rate isn't too high. Or perhaps have group A partially cover the interest of group B because they're lower risk and likely have higher income. I imagine that late fees increase the cost of repayments while debt interest increases the number of payments thus not hindering the ability to make future payments.