Weight: dropped from perhaps 2nd percentile to perhaps 1st percentile. Height: rose from about 10th percentile to about 25th percentile.
I'm not sure whether that means our emphasis on getting food into him is working or not.
If you want to know the exact percentile numbers, you can get the parameters for a model distribution for each month here: http://www.cdc.gov/growthcharts/data_tables.htm
My personal opinion is that you must be feeding him enough to support his growth if he's able to make that big a percentile jump in height. It sounds like he's just using it all for building height immediately instead of keeping any of it in reserve. Are the doctors pushing you to tube-feed, or just encouraging you to keep doing what you're doing, or what?
Did either (or both) of your and Elizabeth's parents keep a baby book where they recorded this information? I found it sort of reassuring to compare my kids' data to their parents'. Howard's weight bothered me less when I could see that his father had been somewhat shorter and even heavier. Maybe Duncan's not as far off his parents' curves as he is off the imaginary "normal" chart.
Our pediatrician isn't really pushing anything; he was originally of the opinion that it was not dietary since head circumference and behavior were progressing fine, but I think now he's deferring to the endocrinologist. We agreed with the endocrinologist to try feeding him more for three months before getting more invasive testing, and we're half way through that period. If he continues on his recent trajectory, he'll be average height and off the chart low in weight by then, and I'll be very interested to see what her assessment is, after she makes the nurses remeasure him and is convinced the measurements are real.
He's currently 5th percentile in weight for height. I don't have a chart for myself; I don't think my parents tracked it and my doctors didn't provide a chart, not to mention by Duncan's age I'd had doctors in three different countries. However, my current weight for height is "below 2nd percentile", so I'm not that worried about where he is now. I'm more worried that the weight trajectory is still falling away from the mean; he's on track to be 35 inches and 22 pounds at age 2, which would look pretty anorexic.
I actually suspect the basic issue is late teeth - incisors aren't enough for chewing, and Duncan only recently got his first bicuspid. A drop in milk supply from pregnancy probably didn't help with that. If that's true, he should be fine as more teeth come in. Without knowing for sure, though, it's still something to stress about.