Halo: Reach Achievements

I’ve completed the campaign on normal then, call me an achievement -Yoink!-, I went back and did the 2nd mission, didn’t die, didn’t set foot anywhere near a driveable vehicle, killed at least 7 Moa but still didn’t get either of the Achievements for this, what’s going on? Also on “My XBox” the summary page for Reach shows 235/100 Gamerpoints 19/49 Achievements, yet if you go into the detail I have 20 Achievements totaling 245GP. Even weirder still, if I go to XBox.com it shows the correct totals. WTF is going on?

Obviously meant 235/1000 not 235/100.