My scout is an 8th grade SPL for an 85 member troop. His troop doesn't have separate elections for ASPL and SPL. The scout is elected to ASPL for a 1/2 year term (June COH-Dec COH or vice versa) and then automatically moves up to SPL for the next 6 months. This troop does the same with the patrol leadership positions as well. So my scout had 6 months of training as ASPL before he took over in Dec. When he was serving as ASPL, his SPL was a 10th grade Life Scout. Right now both the SPL and ASPL are 8th grade Life Scouts and OA members (one is Brotherhood, 1 is Ordeal). So they may be young, but they did have scouting experience.
We live in a area with a lot of military families so every so often the ASPL will not get to do SPL and the troop will have to elect 2 officers. This will happen in June since my scout will be finishing up his SPL term and the ASPL is having to PCS with his family. It also happened 2 springs ago for the same reason.
My scout is a little concerned about who will become SPL without the ASPL time so he has taken it upon himself to encourage certain boys with natural leadership ability and a command presence to run this June. Haha, he says he wants to be an engineer but I think he should be a politician!