The "old modules" in 3.305 are for non-Soft-Start Lamp Modules and Wall Switches. The Lamps section is for soft-start modules and Wall Switches.
Understand?
Sometime around 2007 or 2008, X10 decided to re-engineer the lamp modules and wall switches, but didn't change the model number. The newer ones are "SoftStart," (they slowly "ramp up" from an off state to full brightness, instead of instantly coming on at 100%), and can respond to "Extended Dim" commands.
Starting with version 3.302 of AHP, the newer, SoftStart modules are the default "Lamp Modules," and the older ones are in the "Old Lamps non-SoftStart" category. AHP will use "Extended Dim" codes to talk to those modules, but the older modules can't respond to those types of commands.
Therefore, if you have any lamp modules or wall switches that are of the older (pre 2007/8) vintage, they would have worked fine up until 3.302, but then not worked properly afterward, without re-defining them in AHP.
However, it seems that once you change the module type, everything starts working properly again.