In practice or qualifying session the gap represent the difference between the best lap time of the first driver (pole position lap time) and the current one and therefore will never take in account the total laps (as you know in a qualifying session we don't care of the number of laps, only the best lap time is important).
About the "S.Pos" column: you right there is a bug, it's like the program take care of the number of laps and not take care of the best lap time, this bug will be fixed in version 5.06