Paint? Primer? help. [View all]

I had my house primed and painted 2 years ago. It was scraped and primed over old stain and has help up nicely since.
I have a small 'L' on the rear that I did not have done. The stain is about 20 years old and is showing signs of peeling and fading.
The house is 2 1/2 stories, the 'L is only one story and does not get the heavy weather beating that the rest gets.
Can I paint directly over the old stain?
The house had been done twice in these past 15 or so years, the 'L' has never been done since it's initial stain.

I paid for the prime and paint job, I'm afraid there is no more $$$ to pay a contractor to do the addition. I'd like to do it myself. I can handle painting but two coats on 4 sides might do me in.

Can I just paint over the old stain? I would certainly scrape any loose flakes.
I have California Acrylic paint and it would go over old California Acrylic Storm Stain. Same color, except the stain has been changed to a low gloss and the paint is flat.
Advice would be appreciated.