You can use svn log and svn blame or the tortoise equivalents figure out what changed when. The lines you reference did not change in the ximr merge (r6195)
The "if" you mention around line 270 was removed in
r5669 which references
this forum post.
I don't honestly remember all the details, but this change appears to be intentional, with the purpose of ensuring CHDK is always fully in alt mode (rather than a mixed / confused state) when a script starts.
If you believe you've found a bug, you should describe the symptoms of the bug.
And this
really doesn't belong in the
chdkptp sticky thread, since it refers to
CHDK code.