A LS mate was saying it seems leves reward about 5% of your tnl for completion. thats pretty fair for 10-15 min worth of play time. The issue is the 8 leve limit per 36hrs. However you are playing solo, don't expect the same rate of gain as someone who puts forward more effort (time).

I'm hoping that with 1.19 leves are put on a reduced timer and kept at this current sp reward rate.