[Kenwood] TL-922A question

[rb]

I see I'm going to need some straightening out on my thinking of using linear amps.   I thought my exciter (Yaesu FT-101zd) would drive it full output with maybe 50 watts or so.  

I'm finding I run maybe 150 watts into the TL0922A, and it still puts out maybe 500 CW watts.

Now, I have a 160' dipole, feed with 450ohm ladderline.   It comes into the house through a 4:1 toroid, just outside my shack.   I have a good 3KW antenna tuner (with roller coil).   My other exciters load it fine barefoot.  

Using my TL-922A, I have the feeling that everything is "right", and it seems to like my ant situation.   I guess my big questions are:

A.   Why does it take 150 watts to get 500 CW out?

B.   What do I need to do to get more output?