Frequency of cleaning depends a lot on the conditions in which the gun is being used. For instance:
My duck gun (gas auto) gets cleaned every 25-30 shots. I've determined, over several seasons, that that's when it starts getting loaded up with powder, cattail seeds, bulrush stems, twigs, cordgrass, mud, etc., and the action starts to slow down.
My pigeon gun (also gas auto, like the A400) will go well over 300 rounds (I've gone as high as 500) and will still be functioning perfectly.
I clean both guns the same way, and use the same lubricants on both. The difference; cleaner shells and cleaner conditions the one gun is used with/in.
If I were you, I'd take advantage of my experience and keep track of the number of shells you put through the gun as you shoot it. Don't clean it until it starts acting up. That way you'll have a good idea of when to clean your gun, based on your conditions.