Negash Lodge in Woliso now charges 506 birr and above for their rooms, it seems that the place has been privatised and the prices almost tripled from what you mention in your guidebook
did an overnight trip to Wenchi. It is really beautiful. I stayed in
Ambo at the Abebech Matafaria Hotel and paid 140 birr for a single (with a queen size bed). Full breakfast at the hotel was 25 birr.
The hotel is also building at lodge at the entrance to the Wenchi crater lake. Looks like it should be finished before the end of the year.
Gudar falls charge 10 birr entrance for foreigners and 10 birr for the camera. 3 birr for Ethiopians.
In Jimma I stayed at the SYF hotel (the only place with a room, as it was graduation weekend), very much overpriced at 200 birr, water only occasionaly, mostly bucket showers, electricity only every other day (like most places in Ethiopa at the moment) There is nice juice in Jimma, but I (with my verymuch africanised intestines) still caught some bug and was pretty sick for about 24 hours. The restaurant at Syf has good national dishes (excellent shiro tagamino) and decent pasta (a bit greasy, but tasty), but it sharges more if you order from the English menu.
I almost missed my plane in Jimma on the way back, as there was a schedule change (and the flight lest 1 hour earlier than planned). I never got the call (what with the network being really bad, it is no wonder). I would suggest that even if you are told in Addis that your return has been confirmed, you should check with the EA the day of your flight, or the night before.