I wouldn't be worried either. 10kg is still a good gain, and if its a bit up and down I wouldn't have thought would matter too much.
I'd only worry if you were feeling not right, or if you were losing heaps of weight consistently each week with no explanation.
Mmmm, good on you about the chocky! I think I might employ a similar strategy after I've had this baby (even though I've not any issues with blood sugar, only with weight because of a serious carb addiction!). What a wonderful idea.