Hi. Who d hell told u ur lo is chubby? They are supposed to be chubby, they are storing the fat which they will use when they start moving around and get active. Unless ur doctor told u that ur lo is on the overweight/obese side (don't even know if thats possible at 13 weeks) than I woudn't even think about it!
Sleeping through the night at 13 weeks is fantastic, if u take away the df I am pretty sure ur lo will end up waking up at night for feeds. U r right, df gives los the calories to keep them going through the night.
If u r worried about ur lo gaining weight too fast have her checked out by ur GP. As far as I know a lot of it depends on their birth weight, my dd was 6lb when she was born so she didn't take 180 mls untill she was about 5 months, my friends son was 11lbs at birth and is taking 150 mls at barely 2 months.
I wouldn't stress about their weight unless its decreasing. Looks like ur lo is doing great so don't mind someones ignorant comments.