ching, u miss up premium and discount.
when we said rmb discount, it means that the forwards compare to current value is like 貶值。
in your example: current 6.135 rmb = 1USD, Dec: 6.195 rmb = 1USD. so it looks like RMB will 貶值. this is discount.
Same as my example above, i claim that 投資者未必真係expect RMB貶值,而係因為息差
i think all that relies on the fact that interest rate parity holds for your equation? in any case the fact that the CNY has a closed capital account at the moment means that it wont have large fluctuation as everything is government regulated