I first posted this under the Lightroom but I have since determined that it is not specific to LR, as I get exactly the same results with Photoshop. So I think it is a problem with OSX Lion.
On roll paper (I'm using 24", but I see the same thing with 16"), if I specify the length to be (say) 18", it cuts at about 19". I say about because it is not exact. I get the same result each time, so it is not random. And the print is not centered on the length.
I have been around and around with Epson (the Long Beach group, which should know what they are doing). They have not been able to help. I also talked to Adobe LR, and also no help.
I don't think I am the only one experiencing this. When I posted this to the LR section, Eric Chan wrote that he had no problems, but he is using OSX 10.6. I really have no interest in going back a step in OS, so please don't suggest that.
I do know there is one really good solution (OK, really a major work around). That is to buy ImagePrint. I actually did this, and yes it works perfectly.
But really, shouldn't LR and Lion do exactly what I tell it to do in Lion?