No, calculation on profile page is made from shares of current round and it is expected to be very inaccurate. Actually 1Ghash from real 1.3 Ghash is pretty good estimation, nothing to worry about.

better if you check your daily reward. This MHash on your profile is hidden for the reason, that this calculations is not accurate. It varies wildly. Prettly likely that you will obseve also 1600 MHash/sec for a brief while.