B.M.
T.,
Here's the link to car-seat.org and the answer to your question- yes your seat requires the base to be used.
http://www.car-seat.org/showthread.php?t=59293
I posted this question over on a carseat forum will update with their answer...in the meantime your manual should be clear about this.....I do that the Pegs at one point did require the base to be used all the time unlike other infant seats like Graco Snugrides which can be used without the base if needed. If you don't have the manual anymore you could also call Peg. The Peg website doesn't seem to have old manuals and you want the one specific to your year...they changed their seats quite a bit in the last year.
B.