I'd be happy to double check your chart for you, but honestly, I wouldn't worry too much about it. If you're only about 6 weeks along, the U/S would only be off by a day or 2 either way, not anywhere close to 14 days.
I only have "anecdata", but my milk came in on day 2 with DD (vaginal birth) and not until day 5 with DS (c/s). My midwife thought that my milk production (with DS) was affected by the amount of blood I lost (about 1500cc compared to about 300cc with DD).
Whoa ... is THAT why they gave me so much vaseline at the hospital?? I thought it was for the meconium diapers (which, since my milk was taking it's own sweet time coming in and he was jaundiced, we had for about a week). It never even occurred to me that it could possibly be for something else.