When using a Unity skill, the unit gets +5 to skills and +(Penality in the stat × 2). So if the unit has a -7, it would get +19 (5 + 7×2), but with the active penalty it would only get +12.
When using Xane, he would copy the stats of the nearest unit ignoring his owns debuffs. So would he get the complete +19? Has someone try this?