Mama, ang 1st trimester ultrasound ang most accurate para sa dating talaga, that's what most OBs go by kaya ang Jan 26 is likely your more reliable EDD, not the LMP one. The 2nd trimester one a week later (Feb 02) will still show growth okay naman, pero by that point the dating can be off by a few days, kaya kung significant ang difference between the two scans, better ask your OB which one they'll use for your official EDD since that matters for monitoring. Baby's growth should be fine regardless, one week variation ay normal lang sa ultrasound margins of error, so don't worry too much about that!