It's unfortunately not a miscalculation. Since it's a three week event, the unlock progress via challenges has been spread out for the whole length of the event.
If you want the SMG right now, you'll need to either use in-game currency, or pick one up and rank it to level 10 to unlock the weapon package version (N.B. you won't be able to customise this).
Except I think it is a miscalculation. Some of the people in my clan have the gun already... Most of us (myself included) do not have enough points yet. We all have 105... Somehow they earned enough points sooner. So there's something screwy going on because they all said that they earned it this week naturally and did not buy it. I highly doubt that all of them are lying about not paying for it since we were all in the same grind trying to get the points until we started realizing that some were unlocking it, and some of us are short...
