Well I asked Peter Ting of Massoth about this very issue several years ago.
(Real) LGB decoders have always acted differently to virtually every other make of decoder in that they would operate a function based on a change of state, whereas all of the others that I know of 'on' would mean 'on' and 'off' would mean 'off'. The 'on' is 'on' way of working is a sort of de-facto standard because I haven't found it written down in any standard. Massoth decoders themselves follow the 'on' means 'on' rule. But it is worse than that these LGB decoders would also remember the state of a function over a power off. If say sound was on when power was removed then when power was restored sound would also be on. This could mean that either turning a function 'on' would actually turn it 'on', or it could mean it actually turned it 'off'!
Peter told me that the LGB way of operating functions was something that LGB had mandated to Massoth.
Now usually this doesn't make much difference since a user has ears and can tell if sound is on or not and can press the function button on his/her handset until the desired state is achieved. For a computer assuming 'on' is 'on' the LGB way of working is not good, because it depends on the state of the function when power was last removed. Sometimes when the computer program thought it was turning the sound on it was actually turning it off, because sound was on when power was last removed.
I probably haven't described that very well but it meant for me I had to take special measures in a computer program when it was controlling an LGB decoder.
I am glad MLGB are changing the way their functions operate so that they follow what everyone else does.