Trying to stay to fast too late is bad news on the bigger NGs. You simply cannot get away with it comfortably on an -800!!
The FMC is quite conservative in slowing and will gradually work it's way back to the UP speed, not 210 itself. Once you pop Flap 1 in it reduces to the 1 speed and continues this all the way to REF +5 or more if you've put a wind margin in the FMC APP REF page.
Rushing is just unnecessary stress though.....