You can't look at the last guy to get a line, you have to look at the first guy who is given reserve (most probably not by choice). That's because PBS allows junior guys with preassigned credits (vacation, training) to hold lines ahead of more senior guys without such credits. So if you look at the list there will be a section where there's a mix of some guys getting reserve and some guys getting lines; you need to be ahead of this whole section if you want to reliably hold a line.
Yeah that is why I was looking for real input. The thing on xjet only shows the last line, not the first reserve.