Not quite, you need to be precise on the downstrum so that you can afford to be less precise on the upstrum. (the strings you miss on the way back up should still be ringing from the downstrum).
Long term aim for accuracy both ways.
I am very precise with my downstrums, hardly missing any notes. But when I try to be as precise with the rhythm of my upstrums, my righthand movement becomes a little unnatural (especially when I have to upstrum five strings i.e. the C chord..). When I don't really watch my upstrum and go for the thinnest three or four strings I found out that my rhythm is much better. So for now I can continue playing like this or do I have to pick all the strings when upstrumming?