I just read the whole topic.
There is something highly faulty in thinking that TL-15 warrants having prototype hop drives. I mean, TL-7 obviously doesn't have prototype jump drives, nor even experimental ones!
I'd probably rate experimental (not yet useable) tech as target TL minus one. Prototype, early and mature should all be within the target TL. Or maybe mature would even be target TL plus one.
There is something highly faulty in thinking that TL-15 warrants having prototype hop drives. I mean, TL-7 obviously doesn't have prototype jump drives, nor even experimental ones!
I'd probably rate experimental (not yet useable) tech as target TL minus one. Prototype, early and mature should all be within the target TL. Or maybe mature would even be target TL plus one.