CXA546,

Yes you should see some drop as each pack is turned on depending on the position of the mix valve. The harder the pack is working the lower the pressure will be. There is a difference between the -100 and the -200. The -200 has a flow multiplier off the APU which allows both packs to be run at the same time off the APU. The APU in the -100 did not have the ability to run both packs off the APU.

Lou