I suspect that the reason it was put behind the captain was special and gave the bridge balance. Remember, unlike the other stations, the science station had those two moving consoles on hydrolics. It was probably easier to keep the hydrolics mechanisms stored between the two turbolifts out of the way. For TWOK the hydrolics were removed and they were just on rollers so the station could just be placed anywhere.
Specially there is also more room behind the captains chair than there is on the sides due to the railings. I think when fully extended the two consoles are slightly in the way on the side. I think in TWOK and TSFS you only ever see one panel extended at a time instead of both.