[Amps] RF choke for 160m amp mod

[rfdude@comcast.net]

Hi,
I added another 90microH mounted orthogonally to the existing (also 90microH) when modifying my 30S-1 for 160m.

The unmofidied amp calls for 1.5nF 6KV bypass after the (original) RF choke. 
I mounted 5nF 10KV after the second choke and I was going to switch the 1.5nF (now between the chokes) in and out of the circuit when going from the regular bands to 160m. 
Well it turns out I don't need to, and with it in place I still get about 10% extra output on 160m, so that's one less thing I need to worry about. I have the amp on the air for many hours with no signs of heating or fireworks.
Why am I even bothering with the second choke? However the numbers say I show use it.

If  the PA output has a (magnitude) Z of about 5-6K, and the choke and bypass reactances are about j1000 and -j100 at 2MHz respectively, why shouldn't  I observe a lower efficiency output on 160m, instead I get more! What gives?

thanks for any inputs on this surprising output (pun intended).....
73s
kb3bf chris