At first, couldn't understand and was around 430. Now, I slowly progress:
401... 391... 381... 375... 371 means 28 off.
26 off... 20 off... 18 off... 14 off... What a work!
** one year later**
Still working on it once in a while. Stuck 14 off and no more ideas.
awww... 10 off... there is hope... :D
5 mins later: 8 off and the way I saved 2 more gives me some hope as what to search for...
I was right: 2 mins later, 6 off.
(9 months ago) I was over 400, but when i read Devildude comment, I found the 34 off, too. :D Will keep trying. Uffffff.
EDIT1: 28 off, 26 off, need a huge ''cut'', no idea, where it is, huh. 18 off, jeeezzzz. 14 off :O :/ can't think of anything shorter ... mrrrrrrrhhhh
EDIT 2023, 27th June: Later I found a 2 off, but was completely dry of ideas. So I left it, for a while. I came back yesterday and it took me over an hour to first find a 4 off. Then I kept trying several combinations and today I finally got the 343. The order here truly surprizes me. Would never expect this was the shortest path. Great puzzle.
Not that hard if you really think about it. I would elaborate, but I don't want to spoil the level's cute solution and the fun that comes with figuring it out.