I have a question about framing an interior wall.

The way I have seen it done, you have the bottom plate and top plate and
studs in between, and the bottom plate to be PT since it's resting on
concrete slab. The drywall goes on top.

However, I recently demoed part of my house, and I had to extend existing
walls and build new walls. I did not notice it at the time, but today I
realized that the original construction had nailed furring strips (seems to
be 3/4" x 3") to the bottom plate on both sides. See the picture below:

http://i173.photobucket.com/albums/w...g/P1010352.jpg

http://i173.photobucket.com/albums/w...g/P1010354.jpg

and the drywall actually sit on top of it flushed. I also measured the
ceiling and it's 99" above the slab instead of standard 96", I wonder if
they raised the ceiling so as to accomodate 2 sheets of 4x8 and the strip at
the bottom.

Is there any advantage of doing it this way? I would think the baseboards
will attach better?

I was going to frame the new walls differently, but seeing now how they did
it I think I have no choice but to do the same, or else my drywall will not
touch the ceiling, and I have to buy drywall sheets that match the thickness
of that strip.

Always running into surprises.

MC