I think there have been issues in the past when you combine multiple graphics together, that it takes the information about plot range and such from the first one or the last one and ignores all the others. I don't know if that is the source of your problem or not.
For me with your first Show if I change PlotRange->Automatic to PlotRange->All the result looks fine.
For me with your last Plot your TSte5 is almost exactly equal to 100 across the entire domain. So I believe your calculation to find that is incorrect.