Wow… 
Very immature thought and tempt reply:
In your post
simult_ seems very powerful. Though we have no correct Welf term in .mod (dynare computes it wrongly), we definitely have the correct Utility sequence. I’m not sure whether we are/were able to pin down the correct Welf via:
manually inputing
Welf = Utility + BETA*Welf(1);
into simult_ ?? After all, it is very likely that all the rest variables are unaffected. The only minor modification is this recursive form.
However I guess it’s difficult, because simult_ needs arguments of M_, oo_, options_ (I learned this function today 
), which contain erroneous Welf. We have to first remove the wrong one, then insert the recursive form. How to remove and insert??
For reversing the welfare rank of OSR-SOE and Ramsey-SOE:
I’m now doing my modification on OSR-SOE.mod instead of Ramsey-SOE.mod
( wrong direction? ) Because,
In @littlemacro CESOE or OSRSOE files (they only vary with Taylor params), the steady_state_model; session closes to RamSOE. But comparing with your Born_Pfeifer_2018/Welfare, they still involve rooms to improve.
You may have answered these doubts in your latest post. I’ll take a careful look in following days!