Is it me? Or the nature of the beast?

When I discovered the wonderful world of split lines (thank's to Matt and the Bible) it opened many flexible possibilities for design intent.  But, I also found that if I went back into a feature above the split line features, even in a rolled back state, you destroy the split line elements that you created after the newly edited features.

For example ( I can't show the file because it's still in pre-production prototype) I made a thing with a fancy curved surface.  I couldn't use Wrap feature so I used split line, offset to zero, then thicken cut for engraving the logo.  I go down the tree adding some more features as required by the ID and then marketing comes back and changes the logo.  No problem.  Except, that when I changed the sketch that held the original split lines, I had to re-assigned the split lines.  The logo worked great.  But every split line feature afterwards blew up and had to be completely re entered.  It was a big deal because it was about an hours work.

So, did I do something dumb? or is this a goof in the software?

Thanks, Carter  (SW2010 sp2.1.)