Not sure how often you start out in the middle of a music file with /splay and then to use the .length to determine how what the largest number you can use for a starting parameter is, but your point is good. Anyhow, like I said, if it can't be fixed (and that would include fixing .pos), then it would be good to at least explain this in the help file so people aren't left wondering why the results are incorrect.
Perhaps, for the scenario you mention, a $in*.vbrlength option would be good. Either to be used to get the current $in*.length on songs or to get the $sound().length depending which would work best. I know having the two isn't really different than using $sound instead, but it at least provides accurate lengths for $in* as well as giving you the "wrong" vbr length necessary for your scenario.
I don't really know. Just a note in the help file might be fine, or some way to fix .pos and .length both so they are valid on all files. That would be best, but probably the most difficult.
