Looking carefully gave me the rough idea how to solve it, but some optimisation also necessary to get it right. I can't do better than 106. (13 years a go) Sweet puzzle !
Took me 8 tries.
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EDIT 2023, 28th Jan. - such a cool path. I think it deserves 5 stars. Still teaches good lesson on pipelining despite it was made 14 years ago. a month ago I had 4 off.
finally saw neemo's path :)
good level. The one off wasn't my natural one to try out. Would've missed the "teaching moment" if I hadn't explicitly read the description. Am so proud that I got it on first try... It looks like I start to "understand" a bit more that type of levels. 
Insights