Not really, the book tries to have it both ways. The Imperial Army is TL12 for "reasons", but they don't actually fight like TL12 because they have just enough better stuff to still be at an advantage against the TL 14 Zhos.
To quote the book: "In the current conflict the average Imperial soldier faces an equivalently equipped force and has a slight edge over their Zhodani opponents as a result of access to a quantity of TL15 equipment in critical areas."
So, somehow they are TL12, but their TL12 is actually better than the other guy's TL14.