Rostrum,
Actually for all pregnancies, edd is computed based on gestation age. So yes, u shd follow the 1st edd given to u which is calculated based on ER/ET date.
When u go for scanning, the edd on the printout is computed based on size of bb. So if u hv a bigger bb, edd will seem to be earlier n smaller bb will be later.
U shd try to introduce bottle to bb at abt 4-6 wk old if u r going back to work. Doesn't hv to be every feed, 1-2 feed a day is fine. Main thing is bb learn to accept bottle. It is quite common for bb who hv been 100% latching to reject bottle. There r many mothers who hv gone back to work n their bb almost dun drink any milk during the day but they will marathon latch at night to make up for it.
But this doesn't happen to all bb, some r perfectly fine switching back n forth between breast n bottle,