Windows Phone developers have received an email about the upcoming changes to make mobile operator billing available in more countries. In particular markets from March 2014 this means that there will be an additional deduction from your revenue for these specific markets when mobile billing is used (not for continued credit/debit card purchases). The markets in question are:-
Argentina, Chile, Colombia, Cost Rica, Malaysia, Mexico, Peru, South Africa.
For these purchases Microsoft will take an additional 13.9% of the receipt to cover processing costs leaving you with 56.1% of the "list price" rather than the usual 70%. A suggestion on Microsoft’s "Define pricing and market selection" page is to adjust the price for these markets, but then you’ll be penalising the end users and the increased price might deter customers. Hopefully the potential increase in sales from these markets will show that 56.1% of something is better than 70% of nothing and overall developers will see a benefit from reaching these markets.