>>>>>>>I'm not 100% sure, but, isn't there something in IDB rules that states that if there is an equipment downgrade due to mechanical - or whatever - no compensation is required?

I was at DTW a year or so ago and chatting with a gate agent, and just then he received a memo from DL that he read aloud to the other GA, which stated that in cases of equipment downsizes the compensation would be $200.

I haven't seen this mentioned again on FlyerTalk, and maybe either it was not ultimately implemented, or, for practical reasons it is roundly ignored.